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Hunting Black Holes.


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black holes.
Black hole computer simulation. Image credit: NASA.

Although black holes can’t be seen directly, they’re relatively easy to find. Matter spiraling into a black hole becomes superheated, shines brightly, and is visible across the Universe. A new supercomputer simulation has fine tuned the energy calculations for atoms in the vicinity of a black hole. This is very important, because astronomers working on black holes will base their assumptions on these atomic data. The new calculations bring the potential error rates down to a few percent, enhancing the accuracy of other research.

Super-hot atoms in space hold the key to an astronomical mystery, and an Ohio State University astronomer is leading an effort to study those atoms here on Earth.

Anil Pradhan, professor of astronomy, and his team have used supercomputers to perform the most precise energy calculations ever made for these atoms and their properties. As a result, astronomers - in particular, those hunting black holes - will have a better idea of what they are looking at when they examine faraway space matter using X-ray telescopes.

The results appear in the September issue of the Journal of Physics B: Atomic, Molecular and Optical Physics. And while the paper’s subject matter is highly technical, it tells a story that weaves together atomic physics, Einstein’s theory of relativity, cutting-edge astronomical observations, and some of the world’s fastest supercomputers.

Astronomers have spied seas of super-hot atoms in plasma form, circling the centers of very bright galaxies, called active galactic nuclei. The plasma is thought to be a telltale sign of a black hole; the black hole itself is invisible, but any material spiraling into it should be very hot, and shine brightly with X-rays.

Before anyone can prove definitively whether active galaxies contain black holes, astronomers need to measure the energy levels of the excited atoms in the plasma very precisely, and match the measurements with what they know about atomic physics.

Assuring the accuracy of atomic data doesn’t sound like the most exciting job in astronomy, Pradhan admitted - but it is fundamentally important.

"Most astronomers take it for granted that the atomic data they are referencing are correct - they have to, in order to interpret their observations," he said.

For 30 years, the professor of astronomy has worked on the problem. The new, high-resolution X-ray data gathered by NASA’s Chandra X-ray Observatory and the European Space Agency’s X-ray Multi-mirror Mission-Newton satellite spurred him on. Believing that such high-quality observations demanded good atomic data, he and his team - which is also led by Ohio State senior research scientist Sultana Nahar - decided to make the most precise atomic calculations possible.

After years of writing computer codes and thousands of hours of computing time at the Ohio Supercomputer Center, they calculated the energy levels of high-temperature atoms ranging from carbon to iron - the atoms found in these plasmas.

Some of the previously accepted values for these atoms had acknowledged error rates from 30 percent to as high as factors of two or three. With the new calculations reported in this study, the error for all the atoms has been reduced to a few percent.

This means that from now on, when astronomers record X-ray images of objects in space, they will have a much better idea of what atoms make up the material they are looking at, and the physical conditions inside that object.

The atom that most black-hole hunters are interested in is iron, and that’s where Einstein’s general theory of relativity comes in.

The immense gravity of a black hole should, according to relativity, distort the X-ray signal as seen from Earth, particularly for iron atoms. The signal is a spectrum, and looks like a series of lines, with each atom having its own line. One line in particular, called the iron K-alpha line, appears broadened for X-rays emanating from the center of active galaxies, and it is often cited as a key indication of a black hole.

Thirteen years ago, Pradhan, Nahar, and their colleagues began a study called the Iron Project. Their goal, in part, is to find out why the iron K-alpha line is broadened and what the implications are for X-ray astronomy.

"The most direct observation of a black hole is considered to be the iron K-alpha line," Pradhan said. "So it’s very important to find out whether it’s been broadened because there is a black hole nearby, or if there is some other cause."

He is hopeful that astronomers will apply his new data to studies of the iron K-alpha line and help solve the mystery.

Coauthors on the paper include Claude J. Zeippen and former Ohio State graduate student Franck Delahaye, both of the Observatoire de Paris.

This work was supported by NASA, the National Science Foundation, and the Ohio Supercomputer Center.

Original Source: OSU News Release

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The Secret to Earth’s Shining Auroras.

Aurora seen from the space station. Image credit: NASA.
Aurora seen from the space station. Image credit: NASA.

August 25th, 2006: Auroras appear near to the poles when material from the Sun interacts with the Earth’s magnetic field. Now ESA’s Cluster spacecraft have helped determine exactly how energetic particles are generated that cause the atmosphere to glow so brightly. Cluster has confirmed that the interactions with the Earth’s magnetosphere cause flows of gas travelling more than 300 km/second (186 miles/second) to crash into the atmosphere, generating the light show we see.

ESA’s Cluster mission has established that high-speed flows of electrified gas, known as bursty bulk flows, in the Earth’s magnetic field are the carriers of decisive amounts of mass, energy and magnetic perturbation towards the Earth during magnetic substorms. When substorms occur, energetic particles strike our atmosphere, causing aurorae to shine.

Such colourful aurorae regularly light the higher latitudes in the northern and southern hemisphere. They are caused mostly by energetic electrons spiralling down the Earth’s magnetic field lines and colliding with atmospheric atoms at about 100 kilometres altitude. These electrons come from the magnetotail, a region of space on the night-side of Earth where the Sun’s wind of particles pushes the Earth’s magnetic field into a long tail.

At the tail’s centre is a denser region known as the plasmasheet. Violent changes of the plasmasheet are known as magnetic substorms. They last up to a couple of hours and somehow hurl electrons and other charged particles earthwards. Apart from the beautiful light show, substorms also excite the Earth’s ionosphere, perturbing the reception of GPS signals and communications between the Earth and orbiting satellites.

A key issue about substorms has been to determine how they fling material earthwards. The so called 'Bursty Bulk Flows’ (BBFs), flows of gas that travel at over 300 kilometres per second through the plasmasheet, were discovered in the 1980s and became a candidate mechanism.

Observations suggested that BBFs were relatively small and typically lasted only 10 minutes, casting doubt on whether BBFs could play a major role in the magnetic substorm phenomenon. There was also doubt as to whether BBFs took place for all substorms.

Now these doubts are challenged by a statistical study of BBFs and magnetic substorms by Dr Jinbin Cao, Key Laboratory of Space Weather, CSSAR, Beijing, China, together with American and European colleagues.

Using observations of the central plasmasheet collected by three satellites of ESA’s Cluster mission during July – October of 2001 and 2002, Cao and colleagues found 67 substorms and 209 BBFs. When they used the observations of only one spacecraft, they found that 78 percent of substorms are accompanied by at least one BBF. However, by combined observations from three out of the four Cluster spacecraft, they discovered that 95.5 percent of substorms are accompanied by BBFs. "For the first time, it seems possible that all substorms are accompanied by BBFs", says Cao.

Another key result of this work is that the average BBF duration is longer than previously estimated. Single satellite observations confirmed past results that the BBF duration was around 10 minutes.

However, by combining the data from three of the Cluster spacecraft, the observations reveal an average duration almost twice as long: 18 minutes and 25 seconds. So again, the multiple spacecraft data offered by Cluster was found to reveal more about the Earth’s magnetic environment than data collected by single spacecraft.

"These new results by the Cluster mission clearly show that multi-point observations are the key to understanding the magnetic substorm phenomenon," says Philippe Escoubet, Cluster and Double Star Project Scientist of the European Space Agency.

Original Source: ESA News Release

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Did Mariner IV Pass Through a Comet’s Tail?

Mariner IV encounter with Mars. Image credit: NASA/JPL.
Mariner IV encounter with Mars. Image credit: NASA/JPL.

August 25th, 2006: On July 14, 1965, NASA’s Mariner 4 made the first successful flyby of Mars; after six spacecraft had already failed to reach the Red Planet. It passed only 10,000 km (6,200 miles) above the surface of the planet, and sent back 22 pictures. Two years later it passed through an intense shower of meteoroids, more ferocious than anything we’ve seen here on Earth. Meteor expert Paul Weigert thinks the spacecraft might have passed close to comet D/Swift, and the meteoroids came from the comet’s tail.

On July 14, 1965, Mariner 4 swooped over Mars. It was a moment of high drama. Six other probes had already tried to reach Mars and failed–most malfunctioning before they even left Earth. Since the days of H.G. Wells (The War of the Worlds, 1898), people had been hearing about life on Mars and they were ready to see the canals and cities. But the wait was becoming excruciating.

With flawless precision, Mariner 4 dipped less than 10,000 km above the planet’s surface and took 22 pictures. Mars was covered with desert sand and ancient craters. No cities. No canals. No Martians. No one would ever look at the red planet the same way again.

Most histories of the mission end right there, with Mariner 4 buzzing Mars-"the first spacecraft to visit the red planet"– and throwing cold water on a lot of good science fiction. But there’s more to the story. After the flyby, something strange happened to Mariner 4, setting the stage for a 40-year mystery:

Fast-forward to September 15, 1967. Mariner 4 was cruising the dark emptiness between Earth and Mars. Having shot past Mars in '65 without enough fuel to turn around and go back, there was nothing else to do. All was quiet. Fuel was running low. Soon, Mariner 4 would fade into history.

That’s when the meteor storm hit.

"For about 45 minutes the spacecraft experienced a shower of meteoroids more intense than any Leonid meteor storm we’ve ever seen on Earth," according to Bill Cooke, the head of NASA’s Meteoroid Environment Office in Huntsville, AL. The impacts ripped away bits of insulation and temporarily changed the craft’s orientation in space. "It was a complete surprise."

Think about it. Out in the "emptiness" between Earth and Mars, a region of space astronauts are going cross one day if NASA’s Vision for Space Exploration comes to fruition, lurks a dark stream of meteoroids capable of producing a shower more intense than anything we’ve seen in centuries of sky watching on Earth. "Until Mariner 4 stumbled onto it," says Cooke, "we had no idea it was there."

For almost 40 years the source of the shower remained a mystery. But now, meteor expert Paul Weigert of the University of Western Ontario may have cracked the case. The culprit, he believes, is a "dark comet" named D/1895 Q1 (Swift) or "D/Swift" for short.

"Comet D/Swift was first seen in August 1895 by the prolific comet hunter Lewis A. Swift," says Weigert. Swift discovered or co-discovered more than a dozen comets, including 109P/Swift-Tuttle, the source of the well-known Perseid meteor shower. Unlike his other comets, however, "D/Swift quickly vanished. The comet was last spotted in February 1896 heading out of the inner Solar System, and it has never been seen since, even though its orbit indicates it should come back and brighten every 5 years or so."

(Note that the prefix D/ indicates a lost or broken-up comet, one that was well-observed on one or more occasions, but which failed to reappear as expected.)

What happened to D/Swift? "The comet may have disintegrated," says Weigert. Comets are notoriously fragile and sometimes a little sunlight is all it takes to make them crumble. Comet D/Swift probably overheated when it passed by the sun in 1895 and later fell apart.

D/Swift was mostly forgotten until last year when Bill Cooke wondered if "some old D/ comet" might be responsible for the Mariner 4 episode. Comets, especially disrupted comets, leave a stream of debris in their wake as they orbit the sun. If Mariner 4 passed through such a stream, "it would have been sandblasted."

He asked Weigert, a friend and colleague, to look into it. Weigert began to examine old comet data and-voilą-"Mariner 4 was close to the orbit of Comet D/Swift at the time of the meteor encounter."

Amazingly, Mariner 4 was not merely close to the comet’s orbit, it may have been close to the comet itself. "According to our calculations, the [possibly shattered] nucleus of D/Swift was only 20 million kilometers from the spacecraft." As distances go in the solar system, that’s nearby.

"It’s like in Star Trek when Enterprise stumbles across a comet in the middle of deep space. Of course, that’s crazy," says Cooke. "Space is so big, the chances of running across a comet are almost nil." Yet this may be what happened to Mariner 4.

Mariner’s cameras weren’t turned on at the time, so a comet could’ve passed by unnoticed-except for the jostling of comet dust. Telescopes on Earth saw nothing, but that’s no surprise. An old, shattered nucleus wouldn’t necessarily glow. It all makes sense.

Case closed?

Weigert still has doubts. "The complicating factor is that, because D/Swift was seen for only a short time in 1895-96, its orbit is not terribly well-known. Our extrapolations could be wrong. We’re in the process of collecting more observations from 19th century archives and re-analyzing them. Soon, I hope there will be enough information to convict or acquit Comet D/Swift."

This investigation may lead to others. "The space between Earth and Mars is probably criss-crossed by old debris streams," says Cooke. Weigert’s methods can be used to find some of them, "so the next meteor storm won’t be such a surprise."

Original Source: Science@NASA News Release

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STS-115 Brings More Power to the Station.

The crew of STS-115. Image credit: NASA.
The crew of STS-115. Image credit: NASA.

August 24th, 2006: STS-115 is an ambitious mission that returns the focus of human spaceflight to building the International Space Station, bringing new capabilities to the ISS. While a song by John Lennon asserts that revolution will bring power to the people, it will be a new set of solar arrays and its ability for rotation that will provide more power to the space station.

STS-115, the upcoming shuttle mission scheduled to launch on August 27 marks a shift in shuttle operations from Return-to-Flight to a return to the construction of the International Space Station. The last construction mission for the ISS flew in November of 2002 on the flight previous to the Columbia accident, and clearly NASA looks forward to moving on and getting back to station assembly. However, STS-115 not only has a full plate of construction duties, but must also perform the all the CAIB (Columbia Accident Investigation Board)-induced safety procedures that were tested on the past two shuttle flights, including inspecting the heat resistant tiles with the shuttle’s robotic arm and performing a pirouette with the shuttle as it approaches the station, making the underbelly visible to cameras onboard the ISS.

"Flight day two, we have a very, very full day with the inspection," said astronaut Brent Jett, commander of the mission. "So we go from launch day, right in to flight day two inspections, right in to flight day three docking, then the first spacewalk, the second spacewalk, solar array deploy and then another spacewalk. The timeline is a big challenge."

The primary payload for STS-115 is the combined P3/P4 Truss sections that include a set of power-generating solar arrays, the second of four planned sets of solar wings for the station. The new arrays will add over 8,000 square feet of surface area to the ISS and combined with the two girder-like truss sections adds 17 tons to the mass of the station. But more importantly the arrays will more than double the available electrical power, bringing at least 78 additional kilowatts to the station. That’s enough to supply the electrical needs of almost 40 average homes on Earth, (based on 2 kilowatts of power each.) Subsequent construction missions will add new power-hungry science modules to the station and at long last, scientists and astronauts hope, turn the ISS into the science platform for which it was advertised.

A new accessory for the P4 solar arrays is the addition of the Solar Alpha Rotary Joint (SARJ). This mechanical joint is 10 feet wide, and is the largest mechanism ever designed to operate in space. The SARJ rotates the entire truss segment and allows the arrays to swivel so that the face of the solar panels is always turned toward the sun. Combining the SARJ with another moving joint called the Beta Gimbal Assembly allows the arrays to rotate on two axes. If it all works as planned, the arrays will be moving continuously as the station orbits the earth, obtaining the maximum amount of sunlight, thus providing the greatest amount of power.

"The attitude of the station, of course is adjustable, but some attitudes are more favorable from a propulsion point of view and a control point of view than others," said STS-115 spacewalker Joe Tanner. "And so you really want the solar arrays pointing at the sun perpendicular to the sun’s rays, so that you can get the maximum collection of energy."

Because of the delays in getting this mission off the ground, STS-115’s crew has the distinction of boasting the longest training period of any previous crew, over 4 years. The astronauts who will conduct the three spacewalks include three swimmers and a gymnast. Tanner, who swam competitively for the University of Illinois, will be making his fourth spaceflight, and is a veteran of 5 spacewalks. He is probably most famous for doing an on-orbit fix of the first set of the ISS’s solar arrays back in 2000. Panels of the array stuck together while it was being deployed causing one of the guiding cables to come loose, and Tanner returned the errant cable to the spool where it belonged. New procedures, such as warming the panels before deploy, are in place to try to avoid a similar problem on this mission.

Teaming up with Tanner on EVA 1 and 3 is Heide Stefanyshyn-Piper (Stefanyshyn rhymes with definition). She learned to swim in the lakes of her home state of Minnesota, and before joining NASA worked as a diver for the Navy, conducting underwater repair and salvage operations on naval ships. This will be Stefanyshyn-Piper’s first spaceflight.

EVA 2 pairs up Dan Burbank, a member of the Coast Guard who is on his second spaceflight, with Canadian astronaut Steve MacLean, who also has been to space once before. MacLean was at one time a member of the Canadian National gymnastics team. All four spacewalkers will need the grace, dexterity and strength known to swimmers and gymnasts for their very ambitious and arduous planned EVAs. Translating across the growing station requires the spacewalkers to have three 85-ft long safety tethers. The astronauts will have to bring numerous battery packs on each spacewalk for the cordless drill used in space, the Pistol Grip Tool, as they will be removing launch locks and restraints (there are two dozen launch locks on the SARJ alone), installing brace beams and struts, as well as removing some unneeded equipment and retrieving a science experiment. The astronauts will use a spacewalking fanny-pack known as the Transfer Bag in which to store all the equipment that is removed or replaced.

Pilot Chris Ferguson, who will assist with the operations of the station and shuttle robotic arms said that STS-115’s mission is important for the future of the ISS. "We’re setting the stage for what will be the continued development, the addition of the Japanese module and the European module," he said. "So, we’re laying the groundwork for what’s to come in the next couple of years."

Written by Nancy Atkinson

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Astrophoto: Fleming’s Triangular Wisp by Steve Cannistra.

Image:  Fleming’s Triangular Wisp. Image by: Steve Cannistra.
Image: Fleming’s Triangular Wisp. Image by: Steve Cannistra.

August 24th, 2006: Evidence of Astronomy has been found in most ancient cultures. The Egyptians, the Babylonians, the Mesopotamians, the Chinese- and in the New World- the Mayans, the Aztecs and the Anasazi all tracked the movement of stars across the heavens. Astronomy has always been a practical endeavor arising from a fundamental need to anticipate the seasons. Astronomy’s utility didn’t stop there, however. Interpreting the motion of the stars also helped the traveler in ancient and not so ancient societies- particularly those hunting far from familiar landscapes, journeying on long trading missions or sailing out at sea without landmarks. But, in each of these long ago civilizations, what became of the individuals who made the fundamental astronomical discoveries that future generations have taken for granted

Their names have been sponged from our collective memory over the centuries. Even today, our use of selective retention persists. For example, what names come to your attention when you consider the great minds of Astronomy? Ptolemy, Copernicus, Kepler, Galileo, Halley are names that may rush forward. Hubble, Sandage, Hoyle, Sagan, Hawking and dozens more also have helped reveal wonders of the Universe that surrounds us. But, these are all men. Are there no women?

Of course, there are women. But the thousands who have and are contributing to Astronomy remain, very much, unsung.

Let’s listen to a song about one such contributor from the late 1800’s- a period of amazing discovery in all the sciences, including Astronomy. It was also a time that saw expanded opportunities for women. However, women were still considered inferior to men. Some of this was even supported by the science of the day. For example, Charles Darwin, like his predecessors, regarded women subordinate because of their role in reproduction. He asserted that women had the simple task of bearing and raising children. While Darwin’s position was based on his direct observations of nature, others used craniological data and the laws of physics to underscore this mistaken belief. Scientists and non-scientists became similarly convinced and argued against women becoming politically active, overly educated or too involved in science- an unfortunate situation whose refrain still partially echoes into the 21st Century.

But, situations and determination, in combination, have enabled women to make significant contributions- such as Williamina Fleming, who discovered the scene that accompanies this article.

Williamina Fleming was Scottish by birth and moved with her husband to the United States at the age of 21. Within a year of their arrival, while pregnant with their son, her husband abandoned her then fate interceeded. Desperate for resources to support her new infant, Williamina secured a position in the household of Professor Edward Charles Pickering. He was the eminent director of the Harvard College Observatory , he later co-founded the AAVSO and she became his maid. Pickering’s work at the observatory focused on variable and double stars using cutting edge tools like photography and spectroscopes. This generated a enormous amounts of raw data that was useless with out further analysis. For example, under Pickering’s direction, the observatory amassed over 250,000 photographic plates. For all of the romance and wonder associated with Astronomy, in practice, astronomers deal with numbers- lots of numbers. Astronomical analysis is repetitive, tedious, exacting work and Pickering was plagued by the inaccuracies and disorganization of his male subordinates.

According to legend, Pickering finally became frustrated and declared that his maid could do better! It was an amazing and pivotal turn of events for this young person! Thus, Williamina was hired, in 1881, to perform clerical and mathematical work under Pickering at the Harvard Observatory. She was now about age 23.

Williamina quickly proved herself to be an asset. She created a system of classifying stars based on their hydrogen content. She was then placed in charge of dozens of women who were hired to perform mathematical analysis- the type of calculations that, today, would be handled by electronic computers. Interestingly, these people were called "computers"! She also edited the Observatory’s publications and in 1906 was made an honorary member of London’s Royal Astronomical Society.

In short, Williamina’s biography would make a great movie!

She is credited with the discovery of 10 novae, over 310 variable stars and 59 gaseous nebulae including the wispy nebula in this picture, first seen in a photographic plate she was analyzing. Unfortunately, it was the custom of the day for a researcher to credit discoveries to their immediate superior. Thus, Flemming’s Triangular Wisp is more commonly known as Pickering’s Triangle- one of the few off key notes in this song about the astronomer named Williamina Fleming!

The scene in the accompanying image displays a place, about 2,600 light years from Earth, in deep space toward the northern constellation of Cynus. It’s part of a larger nebula, called the Veil Nebula Complex, seen in a prior Astrophoto featured here. These wisps are all that remain of a massive star that exploded long ago.

This dramatic close-up was produced by Steve Cannistra from his dark sky-observing site in North Smithfield, RI. Steve is a physician at an academic medical center in Boston, MA during the day and an avid astronomer during nights when his responsibilities permit. This image was taken through a modest four-inch telescope and a 3.2 mega-pixel astronomical camera during mid-July, 2006. It represents a six-hour exposure.

The colors are not as you would see them were you to travel much closer to the place seen telescopically in this image. This picture was produced with special filters that only pass the light emitted by hydrogen and oxygen atoms floating in the vacuum of space. Steve has pioneered the production of beautiful deep space images using only two filters. In this example, the color red was assigned to light his camera gathered from hydrogen, blue was used for oxygen and green was synthetically created from the difference between the first two. This approach to astrophotography enables both a view of the subject being studied as well as its molecular composition.

Do you have photos you’d like to share? Post them to the Universe Today astrophotography forum or info@universetoday.com them, and we might feature one in Universe Today.

Written by R. Jay GaBany

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Pluto’s Out of the Planet Club.

Only 8 planets now. Image credit: IAU.
Only 8 planets now. Image credit: IAU.

August 24th, 2006: Last year we had 9 planets. Recently we were informed it would grow to 12. Now we’ve only got 8. The International Astronomical Union, currently meeting in Prague, voted on August 24, 2006 to demote Pluto down from planethood status. Now Pluto, Charon, Ceres and the newly discovered 2003 UB313 (aka Xena) will merely be known as "dwarf planets". Under the new definition, planets must orbit a star, be spherical in shape, and clear out their neighbourhood of orbital debris. Pluto has failed to fulfill the third requirement, so it’s out of the planet club.

It is official: The 26th General Assembly for the International Astronomical Union was an astounding success! More than 2500 astronomers participated in six Symposia, 17 Joint Discussions, seven Special Sessions and four Special Sessions. New science results were vigorously discussed, new international collaborations were initiated, plans for future facilities put forward and much more.

In addition to all the exciting astronomy discussed at the General Assembly, six IAU Resolutions were also passed at the Closing Ceremony of the General Assembly:

1. Resolution 1 for GA-XXVI : "Precession Theory and Definition of the Ecliptic"
2. Resolution 2 for GA-XXVI: "Supplement to the IAU 2000 Resolutions on reference systems"
3. Resolution 3 for GA-XXVI: "Re-definition of Barycentric Dynamical Time, TDB"
4. Resolution 4 for GA-XXVI: "Endorsement of the Washington Charter for Communicating Astronomy with the Public"
5. Resolution 5A: "Definition of 'planet’ "
6. Resolution 6A: "Definition of Pluto-class objects"

The IAU members gathered at the 2006 General Assembly agreed that a "planet" is defined as a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

This means that the solar system consists of eight "planets" Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. A new distinct class of objects called "dwarf planets" was also decided. It was agreed that "planets" and "dwarf planets" are two distinct classes of objects. The first members of the "dwarf planet" category are Ceres, Pluto and 2003 UB313 (temporary name). More "dwarf planets" are expected to be announced by the IAU in the coming months and years. Currently a dozen candidate "dwarf planets" are listed on IAU’s "dwarf planet" watchlist, which keeps changing as new objects are found and the physics of the existing candidates becomes better known.

The "dwarf planet" Pluto is recognised as an important proto-type of a new class of trans-Neptunian objects. The IAU will set up a process to name these objects.

Below are the planet definition Resolutions that were passed.

RESOLUTIONS
Resolution 5A is the principal definition for the IAU usage of "planet" and related terms.

Resolution 6A creates for IAU usage a new class of objects, for which Pluto is the prototype. The IAU will set up a process to name these objects.

IAU Resolution: Definition of a Planet in the Solar System
Contemporary observations are changing our understanding of planetary systems, and it is important that our nomenclature for objects reflect our current understanding. This applies, in particular, to the designation 'planets’. The word 'planet’ originally described 'wanderers’ that were known only as moving lights in the sky. Recent discoveries lead us to create a new definition, which we can make using currently available scientific information.

RESOLUTION 5A
The IAU therefore resolves that "planets" and other bodies in our solar system be defined into three distinct categories in the following way:

(1) A "planet"1 is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

(2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape2 , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects3 except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".

Original Source: IAU News Release

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Supermassive Black Holes Prevent Star Formation.

Artist illustration of a supermassive black hole. Image credit: NASA/JPL.
Artist illustration of a supermassive black hole. Image credit: NASA/JPL.

August 24th, 2006: The supermassive black holes thought to be lurking at the heart of most galaxies could create such a hostile environment around them that they prevent the formation of new stars. This is according to new research assisted by NASA’s Galaxy Evolution Explorer (GALEX). The space-based telescope observed more than 800 galaxies, and found that the larger galaxies had fewer young stars. Astronomers believe that jets blasting out of supermassive black holes could clear out gas and dust; potential star forming material.

Supermassive black holes in some giant galaxies create such a hostile environment, they shut down the formation of new stars, according to NASA Galaxy Evolution Explorer findings published in the August 24 issue of Nature.

The orbiting observatory surveyed more than 800 nearby elliptical galaxies of various sizes. An intriguing pattern emerged: the more massive, or bigger, the galaxy, the less likely it was to have young stars. Because bigger galaxies are known to have bigger black holes, astronomers believe the black holes are responsible for the lack of youthful stars.

"Supermassive black holes in these giant galaxies create unfriendly places for stars to form," said Dr. Sukyoung K. Yi of Yonsei University in Seoul, Korea, who led the research team. "If you want to find lots of young stars, look to the smaller galaxies."

Previously, scientists had predicted that black holes might have dire consequences for star birth, but they didn’t have the tools necessary to test the theory. The Galaxy Evolution Explorer, launched in 2003, is well-suited for this research. It is extremely sensitive to the ultraviolet radiation emitted by even low numbers of young stars.

Black holes are monstrous heaps of dense matter at the centers of galaxies. Over time, a black hole and its host galaxy will grow in size, but not always at the same rate.

Yi and his collaborators found evidence that the black holes in elliptical galaxies bulk up to a critical mass before putting a stop to star formation. In other words, once a black hole reaches a certain size relative to its host galaxy, its harsh effects become too great for new stars to form. According to this "feedback" theory, the growth of a black hole slows the development of not only stars but of its entire galaxy.

How does a black hole do this? There are two possibilities. First, jets being blasted out of black holes could blow potential star-making fuel, or gas, out of the galaxy center, where stars tend to arise.

The second theory relates to the fact that black holes drag surrounding gas onto them, which heats the gas. The gas becomes so hot that it can no longer clump together and collapse into stars.

Other authors of this research include: Drs. Kevin Schawinski, Sadegh Khochfar and Sugata Kaviraj of the University of Oxford, England; Dr. Young-Wook Lee of Yonsei University in Seoul, Korea; Drs. Alessandro Boselli, Jose Donas and Bruno Milliard of the Laboratory of Astrophysics of Marseille, France; Tim Conrow, Drs. Tom Barlow, Karl Forster, Peter G. Friedman, D. Chris Martin, Patrick Morrissey, Mark Seibert, Todd Small and Ted K. Wyder of the California Institute of Technology in Pasadena; Dr. Susan Neff of NASA’s Goddard Space Flight Center, Greenbelt, Maryland; Dr. David Schiminovich of Columbia University, N.Y.; Drs. Tim Heckman, Alex Szalay and Luciana Bianchi of Johns Hopkins University, Baltimore, Md.; Dr, Barry Madore of the Observatories of the Carnegie Institute of Washington in Pasadena; and Dr. R. Michael Rich of the University of California, Los Angeles.

Additional information about Galaxy Evolution Explorer is online at http://www.galex.caltech.edu.

The California Institute of Technology in Pasadena, Calif., leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. NASA’s Jet Propulsion Laboratory, also in Pasadena, manages the mission and built the science instrument. The mission was developed under NASA’s Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. Researchers from South Korea and France collaborated on this mission.

Original Source: NASA/JPL News Release

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Sea Launch Lofts Koreasat 5.

Koreasat 5 launch. Image credit: Boeing.
Koreasat 5 launch. Image credit: Boeing.

August 23rd, 2006: A Zenit-3SL vehicle blasted off Tuesday morning from the Sea Launch facility, carrying a Koreasat 5 telecommunications satellite into orbit. The launch occurred at 0327 GMT (11:27pm EDT, Aug 21), and the spacecraft was placed successfully into a geosynchronous transfer orbit about an hour later. The satellite will operate at 113 degrees east, and provide both commercial and military communications services.

Sea Launch Company today successfully delivered the Koreasat 5 communications satellite to geosynchronous transfer orbit (GTO). Early data indicate the spacecraft is accurately positioned and in excellent condition.

A Zenit-3SL vehicle lifted off at 8:27 pm PDT (03:27 GMT, Aug. 22) from the Odyssey Launch Platform, positioned at 154 degrees West Longitude in the equatorial Pacific. All systems performed nominally throughout flight. The Block DM upper stage inserted the 4,448 kg (9,806 lb) Spacebus 4000 C1 platform to GTO, on its way to a final orbital position of 113 degrees East Longitude. A ground station at Fucino, Italy, acquired the first signal from the satellite shortly after spacecraft separation.

Built by Alcatel Alenia Space for the KT Corporation and Korea’s Agency for Defense Development, the hybrid multi-band satellite will be part of South Korea’s new high-capacity Spacecom System over the Asia-Pacific. This is Sea Launch’s fourth successful mission of 2006 – two additional missions are planned for this year.

Following the completion of the Koreasat 5 mission, Rob Peckham, president and general manager of Sea Launch, congratulated the Agency for Defense Development, KT Corporation and Alcatel Alenia Space. "We take great pride in successfully delivering South Korea’s first dual-use spacecraft," he said. "At Sea Launch, we strive to exceed our customers’ expectations and build collaborative relationships built on honesty and trust."

"I want to extend our thanks to everyone involved in achieving this milestone event. In particular, I want to thank our partners and contractors and the entire Sea Launch team for continuing to build our legacy, one successful launch, one satisfied customer at a time."

Sea Launch Company, LLC, headquartered in Long Beach, Calif., is the world’s most reliable heavy-lift commercial launch service. This international partnership offers the most direct and cost-effective route to geostationary orbit. With the advantage of a launch site on the Equator, the robust Zenit-3SL rocket can lift a heavier spacecraft mass or provide longer life on orbit, offering best value plus schedule assurance. For additional information and images of this successfully completed mission, please visit the Sea Launch website at: www.sea-launch.com

Original Source: Sea Launch News Release

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Star Formation in the Large Magellanic Cloud.

Large Magellanic Cloud. Image credit: Hubble.
Large Magellanic Cloud. Image credit: Hubble.

August 23rd, 2006: This photograph is of an active star formation region in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. This region is referred to as N 180B, and contains some of the brightest star clusters ever discovered. Some of the hottest stars here can be a million times brighter than our own Sun. These stars vent out powerful stellar winds that clear out nearby material and cause interstellar gas to ionize and glow.

This active region of star formation in the Large Magellanic Cloud (LMC), as photographed by NASA’s Hubble Space Telescope, unveils wispy clouds of hydrogen and oxygen that swirl and mix with dust on a canvas of astronomical size. The LMC is a satellite galaxy of the Milky Way.

This particular region within the LMC, referred to as N 180B, contains some of the brightest known star clusters. The hottest blue stars can be brighter than a million of our Suns. Their intense energy output generates not only harsh ultraviolet radiation but also incredibly strong stellar "winds" of high-speed, charged particles that blow into space. The ultraviolet radiation ionizes the interstellar gas and makes it glow, while the winds can disperse the interstellar gas across tens or hundreds of light-years. Both actions are evident in N 180B.

Also visible etched against the glowing hydrogen and oxygen gases are 100 light-year-long dust streamers that run the length of the nebula, intersecting the core of the cluster near the center of the image. Perpendicular to the direction of the dark streamers, bright orange rims of compact dust clouds appear near the bottom right of and top left corners of the image. These dark concentrations are on the order of a few light-years in size. Also visible among the dust clouds are so-called "elephant trunk" stalks of dust. If the pressure from the nearby stellar winds is great enough to compress this material and cause it to gravitationally contract, star formation might be triggered in these small dust clouds. These dust clouds are evidence that this is still a young star-formation region.

This image was taken with Hubble’s Wide Field Planetary Camera 2 in 1998 using filters that isolate light emitted by hydrogen and oxygen gas. To create a color composite, the data from the hydrogen filter were colorized red, the oxygen filter were colorized blue, and a combination of the two filters averaged together was colorized green. The amalgamation yields pink and orange hydrogen clouds set amid a field of soft blue oxygen gas. Dense dust clouds block starlight and glowing gas from our view point.

Original Source: Hubble News Release

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New Crew Exploration Vehicle Named Orion.

Recently renamed Orion. Image credit: NASA.
Recently renamed Orion. Image credit: NASA.

August 23rd, 2006: NASA officially announced today that the crew exploration vehicle will be named Orion. This is the new capsule that will first take astronauts to the International Space Station by 2014, and fly to the Moon by 2020. The agency also recently renamed the crew launch rocket Ares, and the larger cargo rocket Ares V. Orion will be capable of carrying 6 astronauts to the space station, or 4 astronauts to the Moon.

NASA announced Tuesday that its new crew exploration vehicle will be named Orion.

Orion is the vehicle NASA’s Constellation Program is developing to carry a new generation of explorers back to the moon and later to Mars. Orion will succeed the space shuttle as NASA’s primary vehicle for human space exploration.

Orion’s first flight with astronauts onboard is planned for no later than 2014 to the International Space Station. Its first flight to the moon is planned for no later than 2020.

Orion is named for one of the brightest, most familiar and easily identifiable constellations.

"Many of its stars have been used for navigation and guided explorers to new worlds for centuries," said Orion Project Manager Skip Hatfield. "Our team, and all of NASA - and, I believe, our country - grows more excited with every step forward this program takes. The future for space exploration is coming quickly."

In June, NASA announced the launch vehicles under development by the Constellation Program have been named Ares, a synonym for Mars. The booster that will launch Orion will be called Ares I, and a larger heavy-lift launch vehicle will be known as Ares V.

Orion will be capable of transporting cargo and up to six crew members to and from the International Space Station. It can carry four crewmembers for lunar missions. Later, it can support crew transfers for Mars missions.

Orion borrows its shape from space capsules of the past, but takes advantage of the latest technology in computers, electronics, life support, propulsion and heat protection systems. The capsule’s conical shape is the safest and most reliable for re-entering the Earth’s atmosphere, especially at the velocities required for a direct return form the moon.

Orion will be 16.5 feet in diameter and have a mass of about 25 tons. Inside, it will have more than 2.5 times the volume of an Apollo capsule. The spacecraft will return humans to the moon to stay for long periods as a testing ground for the longer journey to Mars.

NASA\’s Johnson Space Center, Houston, manages the Constellation Program and the agency\’s Marshall Space Flight Center, Huntsville, Ala., manages the Exploration Launch Projects’ office for the Exploration Systems Mission Directorate, Washington.

Original Source: NASA News Release

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Book Review: Simple Stargazing.

Simple Stargazing.
Simple Stargazing.

August 21st, 2006: Learning the night sky is pretty intimidating. With enough desire and perseverance it’s achievable, even though thousands of individual stars glitter away. Trying to install that desire and knowledge into the younger crowd is even tougher. Anton Vamplew with his book Simple Stargazing provides a significant aid for just this. With a knack for detail and minimal complications, he cuts the intimidation and adds lots of fun to boot.

Using eighty eight constellations, people have arbitrarily made divisions of all that we see at night. These divisions act as boundaries within which a whole pile of special objects reside; nebulae, stars and galaxies. Constellations themselves are distinguished by the most noticeable light sources. Because of this, they’ve served as beacons for generations of night time viewers. Hence, though constellation boundaries may have changed, their role as signposts and guides remains. Therefore, using these as a basis, astronomers and knowledge seekers alike can navigate through all that fills night’s black skies.

Vamplew has written a book to help learn the stars and constellations, if not with pleasure, at least with lots of fun. His target audience is the non-specialist who ’stand[s] in the backyard / field / outback / savanna / rocky landscape / swamp’. That is, he wants to fairly include everyone no matter where they live on Earth. He also wants to give the opportunity to everyone no matter what their background. Hence, after a one page four step guide on how to look up, he propels the reader into the essentials of star viewing. The beginning portion of the book introduces pertinent phrases and meanings; a light year, the pole star and arc minutes. Following pages describe and provide pictures of the distinguished objects. Usually Hubble shots provide eye candy to emphasize their beauty. After this necessary preamble, he hops into the sky charts which constitute most of the book. These are grouped into four seasons and are further subdivided into constellations seen from the northern hemisphere and others from the southern hemisphere. The charts are clearly oriented and have the constellation figures (not borders) drawn upon them. Following each sky chart is a full or half page description of each of the individual constellations. Vamplew concludes the book with a quick itemized journey through the solar system. With all this, he successfully includes all the basics for learning the way of the stars.

Though the content is fairly standard, Vamplew’s delivery is not. In particular, he’s geared the book to the energy levels and concentration spans of youth. Facts fly fast and furious. Humour abounds as with dictates such as 'Northerly humans start here’. Further, he pokes fun at the standard history of the constellations, such as with his perception of Bootes which is supposed to look like a herdsman but where 'his shape eludes me totally even in my most creative moments’. True as this may be, the light delivery of this and other historical nuances easily makes the shape memorable. And, of course, keeping the shape in memory is crucial once eyes are adjusted to the dark and books can no longer be clearly read. In addition, the bits of history increase the bounty of knowledge that can be gained simply by learning some more about the skies and people’s interpretation.

Another unique element in Vamplew’s book is the twinning of the star charts. That is, one page is the star field without any lines or notations. Adjacent is the identical star page with constellations outlined, as well as some deep sky objects. This provides a great median step in progressing from a fully annotated book. Further, with the charts having a dark blue background, white dots for stars and black for names, they are conducive for viewing with redlights. This just serves to highlight Vamplew’s desire to empower readers to take action and head outdoors.

With this light-hearted approach and rapid delivery, Vamplew’s written a great book for self learners and teachers. Particularly enjoyable is the lack of bias between viewing from northern and southern hemispheres. Further, with sufficient explanations in the early going, the book is quite sufficient to enable parents to teach their children, even when neither has any background in astronomy. Vamplew has ably removed any chance for either to be intimidated. Rather their confidence and enjoyment should increase with every opportunity to put the book into action.

Star gazing is simple, just look up at night. But stare long enough and the stars will draw you up and away from Earth. Anton Vamplew in his book Simple Stargazing provides a fun and informative little reference that will set you on a journey that you can easily share with other night time viewers. So, avoid the confusion on the ground and use this book to soar through the simplicity of the night.

Read more reviews or purchase a copy online from Amazon.com.

Review by Mark Mortimer

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Universe: What’s Up this Week: August 21 - August 27, 2006.

Lagoon Nebula. Image credit: NOAO.
Lagoon Nebula. Image credit: NOAO.

August 21st, 2006: The night is alive this week with everything from bright planets to the first sliver of the returning Moon. This is a great time to explore with binoculars or get out your telescope to pick up some challenging studies.

Monday, August 21 - If you’re up early, be sure to look for the Moon and Venus gracing the pre-dawn skies.

Have you seen any Kappa Cygnid meteors yet? Tonight the fall rate drops off, but be sure to follow the trails of any you do see with binoculars. Now let’s head towards more unusual open clusters - this time in Cygnus. Starting with Gamma Cygni, locate a loose cluster involving Gamma, Do (Dolidze) 43. Now shift two degrees southwest to pick up Do 42 as well. Don’t confuse Do 42 with nearby M29 though, for the two look very similar. For fans of the "Double Cluster" in Perseus, you’ll like the next pairing! Shift another half degree southwest along the body of Cygnus to pick out Do 40 and Do 41. This pretty pair can be placed in the same low power field. By moving another half degree due west, you’ll find highly populated Do 39 and that, too, is a double treat. The brighter clump of stars in the same low power field is IC 4996.

Now for two bright open clusters. The first, Ruprecht 173 is about a degree northwest of Epsilon Cygni. You’ll truly appreciate this heavily populated star cluster! The next is as easy as identifying the constellation of Lyra. Just southeast of bright Vega is a wonderful double for binoculars, Delta 1 and 2 - the easternmost most two stars in the lyre. This bright pair is part of an open cluster known as Stephenson 1.

Tuesday, August 22 - Just before dawn, watch as the last sliver of the Moon slips past both Mercury and Saturn.

With very dark skies tonight, let’s take this opportunity to visit a deepsky study that’s great in telescopes and binoculars. Are you ready for another swim in the "Lagoon?"

Easily located about three finger-widths above the tip of the teapot’s spout (Al Nasl), M8 is one of Sagittarius’ premier objects. This combination of emission/reflection and dark nebula only gets better as you add an open cluster. Spanning a half a degree of sky, this study is loaded with features. One of the most prominent is a curving dark channel dividing the area nearly in half. On its leading (western) side you will note two bright stars. The southernmost of this pair (9 Sagittarii) is thought to be the illuminating source of the nebula. On the trailing (eastern) side, is brightly scattered cluster NGC 6530 containing 18 erratically changing variables known as "flare stars." For large scopes, and those with filters, look for small patches of dark nebulae called "globules." These are thought to be "protostar" regions - areas where new stars undergo rapid formation. Return again to 9 Sagittarii and look carefully at a concentrated portion of the nebula west-southwest. This is known as the "Hourglass" and is a source of strong radio emission.

Wednesday, August 23 - Tonight is New Moon and time for us to have a look at one of the summer’s most curious galaxies - NGC 6822. This study is a telescopic challenge even for skilled observers. Set your sights roughly 2 degrees northeast of easy double 54 Sagittarii, and have a look at this distant dwarf galaxy bound to our own Milky Way by invisible gravitational attraction...

Named after its discoverer (E. E. Barnard - 1884), "Barnard’s Galaxy" is a not-so-nearby member of our local galaxy group. Discovered with a 6″ refractor, this 1.7 million light-year distant galaxy is not easily found, but can be seen with very dark sky conditions and at the lowest possible power. Due to large apparent size, and overall faintness (magnitude 9), low power is essential in larger telescopes to give a better sense of the galaxy’s frontier. Observers using large scopes will see faint regions of glowing gas (HII regions) and unresolved concentrations of bright stars. To distinguish them, try a nebula filter to enhance the HII and downplay the star fields. Barnard’s Galaxy appears like a very faint open cluster overlaid with a sheen of nebulosity, but the practiced eye using the above technique will clearly see that the "shine" behind the stars is extragalactic in nature.

Now look less than a degree north-northwest to turn up pale blue-green NGC 6818 - the "Little Gem" planetary. Easily found in any size scope, this bright and condensed nebula reveals its annular nature in larger scopes but hints at it in scopes as small as 6″. Use a super wide field long-focus eyepiece to frame them both!

Thursday, August 24 - With little or no Moon to interfere tonight, let’s try for another quest - M20.

Located a finger-width above earlier study M8, the "Trifid" nebula appears initially as two widely spaced stars - one of which is a low power double - each caught in its own faint lobe of nebulosity. Keen eyed observers will find that the double star - HN 40 - is actually a superb triple star system of striking colors! The 7.6 magnitude primary appears blue. Southwest is a reddish 10.7 magnitude secondary while a third companion of magnitude 8.7 is northwest of the primary.

Described as "trifid" by William Herschel in 1784, this tri-lobed pattern of faint luminosity broken by a dark nebula - Barnard 85 - is associated with the southern triple. This region is more brightly illuminated due to the presence of the star cluster and is suffused with a brighter, redder reflection nebula of hydrogen gas. The northern part of the Trifid (surrounding the solitary star) is fainter and bluer. It shines by excitation and is composed primarily of doubly ionized oxygen gas. The entire area lies roughly 5000 light-years away.

What makes M20 the "Trifid" nebula, are the series of dark, dissecting dust lanes meeting at the nebula’s east and west edges, while the southernmost dust lane ends in the brightest portion of the nebula. With much larger scopes, M20 shows differences in concentration in each of the lobes along with other embedded stars. It requires a dark night, but the Trifid is worth the hunt. On excellent nights of seeing, larger scopes will show the Trifid much as it appears in black and white photographs!

Friday, August 25 - Somewhere out there, the Moon is furthest from Earth, but not so far away from Mars. Be sure to check IOTA for occultation events.

On this date in 1981, Voyager 2 made a fly-by of Saturn. Eight years later in 1989, Voyager 2 went on to fly by Neptune on this same date. Why don’t we make a "date" tonight to have a look at this distant world? Tonight you’ll find Neptune’s 7.8 magnitude blue disk a little more than a degree northeast of Iota Capricorni.

With little Moon to interfere, let’s have a look at a great binocular target and treasure trove for the telescope - M24. To locate M24, head about four finger-widths north of Lambda Sagittarii. Often referred to as the "Small Sagittarius Star Cloud," this vast region is easily seen unaided from dark sky sites and displays a profusion of faint stars in binoculars. Telescopes will find a dense, but unresolvable galactic cluster - NGC 6603 - embedded near its northeastern border. For those seeking a challenge, look for the Barnard Dark Nebula - B92 - just north of the central region.

Saturday, August 26 - If you’re up before dawn this morning, be sure to look for Venus and Saturn very close to one another.

Did you spot the slender crescent Moon tonight just after sunset? Then be glad it’s gone early as we say farewell to the favorites of the southern Milky Way. Start at G Scorpii and neighboring 7.4 magnitude globular cluster NGC 6441. Head a little more than 2 degrees due north to large and brightly scattered open cluster M7. Shift slightly northwest and include neighboring 10th magnitude globular NGC 6453 in the same low power field. Be sure to visit less than four degrees northwest for the lovely arching loops of "Butterfly" cluster - M6!

Centering on Gamma Sagittarii, go north 6 degrees to find the billowing lobes of the Lagoon Nebula and the "Strawberry Cluster" - NGC 6530. Less than 2 degrees north-northwest brings you to the subtle lobes of the Trifid Nebula - M20. From M20 shift a little less than 6 degrees north-northeast to enter the open magical window of the Small Sagittarian Star Cloud and be sure to catch the faint sheen of open cluster NGC 6602 within it. Less than three degrees north-northeast reveals the gentle "Swan Nebula" floating effortlessly on the ocean of deep space. Perhaps the "Swan" sees the subtle "Eagle" gliding overhead less than three degrees north. Look for its attendant open cluster of stars - M16.

And for last, the densely populated open cluster M11. The "Wild Duck" cluster soars about a fist’s width northeast of M16. Dominated by a single 8th magnitude star, this conically-shaped 3,000 member assembly of stardust easily resolves into innumerable stars with any significant amount of magnification. Through intermediate aperture, this 6000 light-year distant, 250 million year old cluster takes on a new form as several hundred 13th and 14th magnitude members begin to spill outside its V-shaped bounds! Discovered by Gottfried Kirch of Berlin observatory in 1681, the cluster was first noted as stellar by William Derham in the first third of the 18th century. Charles Messier added it to his catalog May 30, 1764.

Sunday, August 27 - Heads up for an occultation event! At 5:30 a.m. PDT asteroid Delia will occult a magnitude 6.9 star on a transcontinental path from SE Canada to the SF Bay area, including Minnesota, Reno and Sacramento. There is always uncertainty in predicted asteroid path locations, but at the moment it seems that the path will favor the northern portion of the Bay Area. In any event, it will be useful for many to observe from their homes, and for some to travel. Expect more information after there is a path update. If there is a possibility that you will be able to observe - mobile or from a fixed location - please respond to IOTA so that a reasonable attempt can be made to distribute observers across the path.

Tonight the Moon sets by skydark, but if you’re looking for a lunar challenge, return to crater Petavius about one-third the way up from the southern cusp just after sunset. This ancient crater is a wonderland of detail when lying on the terminator. Look for its rugged walls interrupted by crater Wrottesley to the northwest and elongated Palitzsch southeast. If conditions are stable, power up to look for a massive, multi-peaked central mountain region, along with a deep scar - Rima Petavius - cutting diagonally across the wavelike floor.

When the Moon has set, look for the southern Crown - Corona Australis. Its hidden jewel is 7.3 magnitude, 28,000 light-year distant globular cluster NGC 6723. Discovered on June 3, 1826 by James Dunlop of New South Wales, Australia, NGC 6723 can be best found by heading less than 7 degrees due south of Zeta Sagittarii. This mid-sized cluster gives a surprising view, but if you’re more north, best catch it at its highest.

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NASA Invests in SpaceX and Rocketplane Kistler.

Falcon 9 launch vehicle. Image credit: SpaceX.
Falcon 9 launch vehicle. Image credit: SpaceX.

August 21st, 2006: NASA has announced a $500 million investment in two aerospace companies: SpaceX and Rocketplane-Kistler to help develop vehicles capable of resupplying the International Space Station after the Space Shuttle is retired. The funding is split between the two companies, and requires them to meet a series of milestones as they develop their vehicles between now and the end of the decade. 20 companies originally submitted proposals to win the Commercial Orbital Transportation Services (COTS) demonstration program contact.

NASA is making an unprecedented investment in commercial space transportation services with the hope of creating a competitive market for supply flights to the International Space Station (ISS).

Two industry partners will receive a combined total of approximately $500 million to help fund the development of reliable, cost-effective access to low-Earth orbit. The agency is using its Space Act authority to facilitate the demonstration of these new capabilities. NASA signed Space Agreements Aug. 18 with Space Exploration Technologies (SpaceX) of El Segundo, Calif., and Rocketplane-Kistler (RpK) of Oklahoma City to develop and demonstrate the vehicles, systems, and operations needed to support a human facility such as ISS. Once the space shuttle is retired, NASA hopes to become just one of many customers for a new, out-of-this-world parcel service.

The venture marks a break with tradition for the 48-year-old space agency. "This is the first opportunity NASA has taken to engage entrepreneurs in a way that allows us to satisfy our needs and lets commercial industry gain a foothold. It could, and should, have profound impacts on the way NASA does business," said Marc Timm, acting Commercial Orbital Transportation Services (COTS) Program executive in NASA’s Exploration Systems Mission Directorate.

Alan Lindenmoyer, manager of the Commercial Crew and Cargo Program Office at NASA’s Johnson Space Center, said NASA’s offer of seed money fulfills President Bush’s Jan. 14, 2004 directive to promote commercial participation in space exploration. The 2005 NASA Authorization Act also calls on the agency to advance space commerce. "We are directly tied to the Vision for Space Exploration and the law of the land," Lindenmoyer said. "COTS marks a significant NASA activity to implement the commercialization portion of U.S. space policy."

The demonstrations are scheduled to begin as early as 2008 and continue through 2010 or later. COTS will be carried out in two phases. Phase 1, unveiled Aug. 18, will include safe disposal or return of spacecraft that successfully dock at ISS and deliver cargo. A follow-on option to demonstrate crew transportation also is planned. Once demonstrated, NASA plans to purchase transportation services competitively in Phase 2.

Partners will be paid only if they succeed. Payments will be incremental and based upon the partners’ progress against a schedule of performance milestones contained in each Space Act agreement. The agreements were tailored to the individual partners and negotiated before partnership selections were made. NASA will gauge progress through site visits and milestone achievements.

Usually, the space agency issues detailed requirements and specifications for its flight hardware and it takes ownership of any vehicles and associated infrastructure that a contractor produces. For COTS, NASA specified only high level goals and objectives instead of detailed requirements where possible, and left its industry partners responsible for decisions about design, development, certification and operation of the transportation system. Because NASA has a limited amount of money to invest, it encouraged the partners to obtain private financing for their projects and it left them free to market the new space transportation services to others.

This model for pursuing of commercial space services is another first for NASA and a reflection on the growing maturing of commercial space capabilities. "This is not a traditional NASA procurement or program. We could change the economics of space flight with this," said Lindenmoyer, whose office oversees COTS. NASA expects use of this model to increase over time as the exploration program unfolds, potentially extending to the provision of power, communications, and habitation facilities by commercial entities.

Limited resources and the space shuttle’s pending retirement created the need for the new service, and the emergence of enabling technology has created a favorable environment for COTS development, according to Timm. Industry interest was keen, with nearly 100 companies submitting expressions of interest and 20 companies submitting initial proposals.

NASA expects that purchasing commercial space transportation services will be more economical than developing government systems of comparable capability. This could free up additional resources for lunar missions and other activities beyond low-Earth orbit.

The biggest benefit of the anticipated cost savings is the opening of new markets for an emerging industry, according to Lindenmoyer. "If we had cost-effective access, many new markets - biotechnology, microgravity research, industrial parks in space, manufacturing, tourism - could start to open. That’s what is so important about this effort."

Original Source: NASA News Release

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Galaxy Collision Separates Out the Dark Matter.

Colliding galaxy clusters. Image credit: Chandra.
Colliding galaxy clusters. Image credit: Chandra.

August 21st, 2006: There’s more dark matter than regular matter in the Universe, and they’re normally all mixed up together in galaxies. But astronomers using the Chandra X-Ray Observatory have found a situation where dark matter and normal matter can be wrenched apart. In a collision between giant galaxy clusters, normal matter, like stars and planets, encounters friction as it passes through hot gas and slows down. But the dark matter isn’t affected by this friction, so it’s able to separate from the regular matter.

Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies. The discovery, using NASA’s Chandra X-ray Observatory and other telescopes, gives direct evidence for the existence of dark matter.

"This is the most energetic cosmic event, besides the Big Bang, which we know about," said team member Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

These observations provide the strongest evidence yet that most of the matter in the universe is dark. Despite considerable evidence for dark matter, some scientists have proposed alternative theories for gravity where it is stronger on intergalactic scales than predicted by Newton and Einstein, removing the need for dark matter. However, such theories cannot explain the observed effects of this collision.

"A universe that’s dominated by dark stuff seems preposterous, so we wanted to test whether there were any basic flaws in our thinking," said Doug Clowe of the University of Arizona at Tucson, and leader of the study. "These results are direct proof that dark matter exists."

In galaxy clusters, the normal matter, like the atoms that make up the stars, planets, and everything on Earth, is primarily in the form of hot gas and stars. The mass of the hot gas between the galaxies is far greater than the mass of the stars in all of the galaxies. This normal matter is bound in the cluster by the gravity of an even greater mass of dark matter. Without dark matter, which is invisible and can only be detected through its gravity, the fast-moving galaxies and the hot gas would quickly fly apart.

The team was granted more than 100 hours on the Chandra telescope to observe the galaxy cluster 1E0657-56. The cluster is also known as the bullet cluster, because it contains a spectacular bullet-shaped cloud of hundred-million-degree gas. The X-ray image shows the bullet shape is due to a wind produced by the high-speed collision of a smaller cluster with a larger one.

In addition to the Chandra observation, the Hubble Space Telescope, the European Southern Observatory’s Very Large Telescope and the Magellan optical telescopes were used to determine the location of the mass in the clusters. This was done by measuring the effect of gravitational lensing, where gravity from the clusters distorts light from background galaxies as predicted by Einstein’s theory of general relativity.

The hot gas in this collision was slowed by a drag force, similar to air resistance. In contrast, the dark matter was not slowed by the impact, because it does not interact directly with itself or the gas except through gravity. This produced the separation of the dark and normal matter seen in the data. If hot gas was the most massive component in the clusters, as proposed by alternative gravity theories, such a separation would not have been seen. Instead, dark matter is required.

"This is the type of result that future theories will have to take into account," said Sean Carroll, a cosmologist at the University of Chicago, who was not involved with the study. \"As we move forward to understand the true nature of dark matter, this new result will be impossible to ignore."

This result also gives scientists more confidence that the Newtonian gravity familiar on Earth and in the solar system also works on the huge scales of galaxy clusters.

"We’ve closed this loophole about gravity, and we’ve come closer than ever to seeing this invisible matter," Clowe said.

These results are being published in an upcoming issue of The Astrophysical Journal Letters. NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency’s Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass.

Original Source: Chandra News Release

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