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Measure distances in the universe.
Type Ia supernovae are used as cosmic yardsticks to measure distances in the universe. That's because they always explode with roughly the same intensity. The theory goes: Type Ia supernovae occur when a White Dwarf star consumes a specific amount of material from a binary partner. It can't hold the extra mass, and so it explodes.
Now observations by the European Southern Observatory's Very Large Telescope have turned up evidence of this stream of material in the region around a recently exploded Type Ia supernova, lending evidence to this theory.
The supernova is SN 2006X, which exploded 70 million light-years away in the spiral Galaxy M100. The ESO observations turned up traces of material that would have been around before the explosion. This material was arranged in shells around the central explosion. Since the explosion is expanding out at a rate of 50 km/s, Astronomers believe the material was ejected about 50 years before the explosion.
This 50 km/s velocity of material is important, because it matches speed of stellar wind pumped out by red giant stars. As the expanding sphere of supernova wreckage crashes into this material from the red giant, it gets absorbed in a way that Astronomers can distinguish.
Astrosphere for July 13, 2007
So much news, so little time. Here's what's new and cool around the astrosphere today.
First the photo. This is the Eagle nebula taken by forum member seeker372011
Next, if you haven't seen already, we've got a cool new logo on the Bad Astronomy/Universe Today forum. Visit this link, check it out. You can even see some alternate designs that were developed. Thanks to Doctor Know for all his help.
Astroprof is working his way through the 7 wonders of space exploration. Here's Mariner 2.
Scientific American has an interesting story on how smog might create beautiful sunsets. But that depends on the colour you like.
Popular Mechanics talks about how the private rocketeers got real.
Derek Breit from the International Occultation Timing Association wanted me to inform everyone that they'll be having their annual meeting on July 20-21 in Pasco, Washington.
If There's Oxygen, There's Life
If aliens visited our Solar System, it would only take them a moment to figure out which planet is the one with all the life on it. That's because our atmosphere has a high percentage of oxygen in its atmosphere. The presence of oxygen in our atmosphere has given scientists the key to searching for life on other worlds. But what if there are purely natural processes, that could confuse the search for life, fooling powerful new space observatories like the Terrestrial planet Finder and Darwin.
Don't worry. A new simulation by a team of US researchers shows that no natural process on a habitable world with liquid water could keep high levels of oxygen and ozone present in an alien atmosphere. If there's oxygen, there's life.
Most of the oxygen (O2) in the Earth's atmosphere was thought to have been generated though photosynthesis. Plants use energy from the Sun, taking in carbon dioxide and releasing O2 as a byproduct. Over time, this oxygen has built up in our atmosphere to its current ratio of 21%, with the rest nitrogen and other trace gases.
This ratio is very important to the search for life in the universe. Over the next few decades, a fleet of spacecraft and experiments are being built that will be so sensitive, they'll be able to analyze the atmosphere of a distant Earth-sized world. Find oxygen or ozone in that planet's atmosphere - so goes the thinking - and you've found a world with life. Like our own planet, some organic process is refreshing the oxygen in the atmosphere, stopping it from reacting away.
One recently canceled spacecraft is the Terrestrial planet Finder, which would be sensitive enough to analyze the chemical constituents of a distant atmosphere. Sadly, this mission was scrapped after budgets were transfered to support the Vision for Space Exploration, which will send humans back to the Moon, and on to Mars. Don't worry, though, the Europeans are working on the problem too with their Darwin mission. And it hasn't been canceled... yet.
These missions (if they do get launched) will be able to spot oxygen and ozone in a distant world's atmosphere. But could they be fooled? Are there natural processes that could generate similar levels of oxygen and ozone? If so, then it would make the search for life extremely difficult, generating false positives that would confuse scientists.
There have been a few scenarios that scientists think might create false positives for life. For example, in a runaway greenhouse planet like Venus, large amounts of Hydrogen could be escaping from a hot, moist atmosphere. Since this Hydrogen is originating from water (H2O), this would leave oxygen behind. If an extrasolar planet was losing its ocean to space, it might fool the detectors.
In another situation, a frozen, Mars-like planet could be large enough to retain heavy gases, but too small to maintain volcanic outgassing. The frozen surface would then inhibit the loss of oxygen, but also not consume it.
The trick to both of these scenarios, though, is that they would exist on planets outside a star's habitable zone. Careful observers would be able to rule them out ahead of time.
A team of US researchers has developed a simulation to see if there are scenarios that could generate false positives, and they weren't able to find anything that would fool future telescopes. The research paper is titled Abiotic Formation of O2 and O3 in High-CO2 Terrestrial Atmospheres, and it was recently accepted into the journal Astronomy & Astrophysics.
They ran many simulations, factoring in all the potential variables that would simulate an Earthlike world, including different rates of volcanic outgassing and ultraviolet radiation.
They weren't able to come up with any scenarios in which a habitable planet with liquid water could generate a false positive result for O2 or O3 that would fool a telescope like the Terrestrial planet Finder or Darwin.
Project Mercury and Project Gemini
Project Mercury and Project Gemini preceded the landing of a person on the Moon. These projects taught the United States how to safely fly humans in to space and out to adventure. Steve Whitfield has prepared a Pocket Space Guide for each of these. Within, he combines smooth narrative with hundreds of both colour as well as black and white pictures to bring a reader complete, colourful little synopses. Their result is a generous reminder of what people can achieve when given a task, no matter how hard.
Both Project Mercury and Project Gemini were extreme engineering marvels as much as Project Apollo. The first placed people above Earth's atmosphere and into space. The second gave control to the pilots of the space craft in order to give them independence and capability with which to complete missions. The third, as most remember, put men upon the lunar surface. Given the definitive goals for each project, definitive results must occur. This hard definition lends well to ready documentation. In consequence, Whitfield can draw on clear objectives and well documented achievements for his pair of books. He does this for a remarkably fine result.
The Project Mercury guide clearly shows the veritable flying phone booth that was the first vehicle the United States used to put men into space. Yet Whitfield doesn't begin there, as the project started well before the Mercury capsule was lofted. First he mentions the unmanned launches of Little Joe and Big Joe. As well, there's a bit on Ham the chimpanzee doing tests, and numerous unoccupied vehicles doing systems tests. Then, after providing a short one paragraph description of each of the 20 preliminary tests within the Mercury project, Whitfield provides a few pages for each of the seven manned launches. Given the allowances in these compact guides, they only provide the barest of technical information and not much else. Therefore, Whitfield gives statistics regarding the space craft and launch vehicle. After, he lists some of the more exciting moments of the flight as well as noting the objectives achieved. These clearly show the increasing confidence and capability of all the people involved in the space program of the United States.
Closing the book, though in reality consisting of about half the pages of the book, Whitfield provides copious colour photographs. These act as wonderful memories of an exciting project, whether they be pictures of the contents of the astronauts' survival package or a sequence of an astronaut while in orbit. Perhaps most fitting is the final picture of the women who trained in parallel with the men in the hopes that they too could go into space.
The outline of the Project Gemini pocket space guide follows that of the Project Mercury guide. However, this project had no unmanned trials, but only a few Agena targeting craft. Hence, this guide focuses solely upon the 12 manned Gemini flights. Again, each of the twelve has a few pages to describe the flight. Where applicable, these include; objectives, the launch, any highlights, and the landing. Concluding the text section is an overview of an interesting plan to use the Gemini craft and launcher to put a man upon the Moon. Of course, this ended up not being necessary, but is a rewarding tidbit nonetheless.
The photograph section in the Project Gemini guide is as varied and plentiful as for the Mercury guide. Each crew and their badge get an entry. There's Ed White doing the first space walk for the United States. An angry alligator and an Agena silhouetted against the Earth's far away surface or other visual testaments. These and others showcase events of the Gemini project vividly and clearly.
Both these guides are great examples of well edited and very detailed works. Given their subject manner, it's easy to get carried away, but they don't do so. These guides summarize the achievements and provide rewarding visual testaments without overweighting the reader with managerial nuances or technical trivia. Certainly, there's a dearth of substance but such is not the intention of a guide. The consequence is that these books practicably do justice but not to excess. Anyone wanting an introduction to human space flight or an overview of multi-year project development will benefit from reading either or both of these two. As well, they're handy references for anyone not wanting to memorize.
Only a few days were needed to transport a human to the Moon. But, more than a decade of research and Discovery were necessary to bring all the abilities together to make this happen. Steve Whitfield provides two guides; Project Mercury and Project Gemini that display two projects that preceded Apollo. Their clarity happily bring these heady times back to the ready fingertips of any reader.
Scientists are Keeping an Eye on a Martian Dust Storm
From time to time, dust storms get going on Mars that can severely limit our view of the Red Planet, and the ability of the Mars Rovers to generate power. There's a storm on Mars right now that NASA scientists are watching carefully to see how it affects the fleet of spacecraft on and around the Red Planet.
This latest storm got rolling during the last week in June in the planet's cratered southern highlands. Over the course of a week, it grew large enough to encircle the entire planet. And now dust is drifting up into the northern hemisphere as well. As the winds sweep dust into the atmosphere, it gets warmer, adding to the storm's power and helping it to pick up more dust.
When the dust gets thick enough, it reflects sunlight away from the surface. This cools the storm and causes it to settle down.
For the NASA spacecraft currently at Mars, this current storm is stealing some of their power. Fortunately, it's currently summer for the Mars rovers, so they're experiencing this dimming during the peak of their energy generation.
The storm will likely last a few months more, and then the atmosphere will clear up again.
Water Vapour Discovered in an Extrasolar Planet
Scientists have reported the first conclusive evidence of water vapour in the atmosphere of an extrasolar planet. Before we load up the spaceships to search for life, however, consider the fact that this planet, HD 189733b, is larger than Jupiter, and orbits its parent star in just 2.2 days. That's hot hot water.
The Discovery was made using the mighty Spitzer space telescope. The Astronomers pointed Spitzer at the parent star, and measured the chemical consistency of its light as the planet passed in front - aka, transited. As the starlight dimmed - blocked by the planet - the chemical constituents of the star changed to show a distinctive pattern. Astronomers know that only water can absorb these specific wavelengths of infrared radiation.
As I mentioned above, this planet is certainly a "hot Jupiter". It contains 1.15 the mass of Jupiter (and 1.25 the diameter), but it orbits its parent star at a distance of only 4.5 million km. In comparison, our own Mercury is a distant 70 million km from the Sun.
It's close, so it's hot. Its atmospheric temperature is about 1000 Kelvin (more than 700 C). With this heat, all the water vapour in its atmosphere can't condense, rain or form clouds.
It's also tidally locked to its parent star, only showing one face to the star at all times (like the Moon and the Earth). This constant facing probably generates fierce winds that sweep around the planet from the day side to the night side.
Like I said, not the best place to find life, but still, an amazing discovery.
Station's New Oxygen Generation System Activated
Apparently astronauts want to breathe. In their mad quest for air, the astronauts on board the International Space Station activated the new US-built oxygen generation system, designed to assist the intermittent Russian Elektron system.
The new oxygen generation system (or OGS) was turned on for the first time on Wednesday. Although there were a few glitches in the beginning, it's been running fine today, and should start producing oxygen later today.
The OGS is capable of producing between 5 and 9 kgs(12 and 20 pounds) of oxygen a day. That much won't be needed today, with only three crew members on board the station, but it'll be critical when it has the full complement of six astronauts on board.
One of the OGS' advantages is that it uses a solid polymer to assist the electrolysis of water into Hydrogen and oxygen. The Russian system uses a liquid called potassium hydroxide. It turns out that this liquid had flowed around inside the Elektron, and clogged up one of the Hydrogen valves, disabling it.
Try Your Skills at Identifying Galaxies
Of all the sciences, astronomy is one that welcomes the assistance of the amateur community. Whether its measuring variable stars, finding supernovae, searching for alien life, or even discovering extrasolar planets, amateurs make a huge contribution to astronomy. And now there's a new way you can contribute: classifying galaxies.
There's a new project called the Galaxy Zoo, which is calling on the public to help classify 1,000,000 galaxies. This research will help reveal whether Astronomers current models of the universe are correct or not.
In order to take part, you go to the Galaxy Zoo website, and then participate in a short tutorial, which teaches you to tell the difference between spiral and elliptical galaxies. It sounds easy, but when the galaxies are seen edge on, it can actually be pretty difficult; but it's a task that's almost impossible for a computer. There are also stars and satellite trails that can mess you up.
Then you take a test to see if you've picked up the skills you need to do the job. Get more than 8 correct and you've met the criteria to join the Galaxy hunting team.
Now that you've got the "eye", the site presents you with currently unclassified galaxies and asks you to categorize them: spiral or elliptical. If it's a spiral, you need to say which way it's rotating, or if it's edge on.
With 1 million galaxies to identify, I suspect the organizers are going to be shocked at how quickly this work is going to come together. Come do your part, it's pretty fun. I categorized 10 as I was writing this article.
European Space Robot Tested Underwater
Normally I wouldn't bring this kind of thing to your attention, but this is just the craziest thing: meet Eurobot. The photo attached to this story really doesn't do it justice. You've got to check out the original http://www.esa.int/esaCP/SEMA6RNSP3F_index_0.html - ESA news release, with a video of Eurobot crawling around a mockup of a space station. It's hypnotic.
All right, I'm getting ahead of myself. Time for details.
Eurobot is a multi-jointed, three-armed robot being developed by ESA. At some point down the road, it'll be lofted to the International Space Station, where it'll crawl around the exterior of the station performing various fix-it jobs; the dangerous and mundane stuff currently done by humans.
Although astronauts will still be needed to complete extravehicular spacewalks, an assistant like Eurobot could do the initial preparatory work, transfer tools and equipment, and help clean up when the work's done. There's a shortage of astronaut time, so any way to make the job run more efficiently would be greatly appreciated.
So this week, a prototype robotic assistant was tested out in a weightless environment. Not space, but a gigantic pool where astronauts train to perform tasks in weightlessness. Eurobot crawled around a mockup of the space station, and engineers were able to put it through its paces. It even interacted with a human astronaut, passing him tools and helping out.
Like I said, though, you've really got to see http://www.esa.int/esaCP/SEMA6RNSP3F_index_1.html#subhead1 the video.
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