New Revelations About the Planet Under Your Feet.
One of the most mysterious places in the solar system is right underneath your feet: the interior workings of the Earth. Since it's impossible to drill down more than a few km under the surface of the Earth, scientists have study how sound waves from earthquakes travel throughout the planet and get reflected as they bump into things. These sound waves have always acted differently than predicted in simulation. scientists now think that iron, crushed under tremendous pressure, can significantly alter the speed and direction of these sound waves.
Discovery Set to Launch Tuesday Morning.
Engineers are still working to troubleshoot a malfunctioning fuel gauge on the Space Shuttle Discovery's external tank, but NASA has pinned down a launch date anyway. If all goes well, Discovery is expected to lift off on Tuesday, July 26 at 1439 UTC (10:39 am EDT). Even if the fuel sensor fails again, managers will go ahead with the launch, as they don't believe there's a risk to the shuttle - there are 3 additional sensors that perform the same task.
What's Next for Deep Impact?
NASA's Deep Impact spacecraft completed its primary mission - excavating a crater in Comet Tempel 1 - on July 4. It was a smashing success, and the spacecraft is now disarmed, like a bee without its stinger. But the flyby spacecraft is still working great and looking for work. NASA is now encouraging proposals from scientists who have some good ideas about what Deep Impact could be used for next. Until a new goal is decided, the agency will put the spacecraft into a parking orbit in the vicinity of the inner planets.
A supernova that Won't Fade Away.
Supernovae are powerful stellar explosions that flare up brightly and then slowly fade away. But not always. One supernova, that exploded in 1979, is blazing as brightly in X-rays as it did when it was first discovered. The discovery was made using the ESA's XMM-Newton space telescope. scientists speculate that a powerful solar wind is smashing into previously ejected material, heated it up until it glows brightly. This is like a powerful light illuminating the whole area, and allowing the Astronomers to study the whole area for years and see how it changes over time.
Dusty Disk Could Hide a New Earth.
Astronomers have used the massive Gemini and W.M. Keck observatories to discover a Sun-like star with one of the warmest, dustiest environments ever seen. The disk around star BD +20 307 is warmer than most other planetary disks because there have probably been recent collisions between planets. In fact the heat is so high, the researchers think a collision recently occurred that matches a cataclysmic event in the Earth's past when a Mars-sized object smashed into our planet, and spun off material that became the Moon.
Go To Original Article From Universe Galaxies And Stars.