Sunday, November 11, 2007

Spitzer Sees a Baby Star Blowing Bubbles


A new image released from NASA's Spitzer Space Telescope shows a baby star blowing bubbles, just like, I guess, a kid with bubblegum. But let's see your kid hurl out material hundreds of kilometres a second across light-years of space. Those are some big bubbles.

The infant star is known as HH 46/47, and it's located about 1,140 light-years from Earth. The star itself is that bright white spot at the middle of the image.

Surrounding the star are two bubbles of material extending out in opposite directions. These bubbles are formed when powerful jets of gas collide with the cloud of gas and dust surrounding the star. The red specks at each end signify hot sulfur and iron gas, where the jets are colliding head on into the gas and dust material.

Astronomers think that young stars accumulate material by gravitationally pulling in gas and dust. This process ends when the star gets large enough to create these jets. Any further material is just blown away into space.

Producing this image was a bit of a technical achievement. The researchers at NASA's JPL developed an advanced image-processing technique for Spitzer data called Hi-Res deconvolution. The process reduces blurring, and makes the image sharper and clearer. With this technique, astronomers were able to make out the details of HH 46/47, and its surrounding bubbles.



Black Holes Linked to Cosmic Rays


You know that big list of unsolved mysteries in astronomy? Well, you can remove, "what causes the highest energy cosmic rays?" Thanks to new research using the Pierre Auger Cosmic Ray Observatory in South America, the answer appears to be: supermassive black holes.

High energy cosmic rays are actually particles - protons mostly - accelerated to tremendous velocities. When they crash into the Earth's atmosphere, they explode in a spray of energy and sub-particles that can be detected here on the surface. Fortunately our atmosphere protects us from damage, but out in space, they're a real threat.

Just a single particle can have the same energy as fast moving tennis ball.

Astronomers have been wondering for years how particles can get boosted to such high energy levels. A massive team of 370 researchers from 17 countries have been working on the answer using the newly developed Pierre Auger Cosmic Ray Observatory, nestled in the mountains of South America.

The observatory is actually an array of detectors spread out over a 3,000 km2 area. As the cosmic rays collide with the atmosphere, the resulting spray of particles are caught by the detectors, which house large tanks of water. The detectors are so sensitive, they can detect a different in timing, which allow astronomers to triangulate the direction the cosmic ray came from. The particles are flung with such energy that they point back to their galaxies, like bullets coming from a gun.

Before the Pierre Auger observatory, cosmic ray detections were rare. Astronomers just didn't have enough data to know where they were coming from. But over the last 3 years, the observatory has recorded a million cosmic rays, including 80 of the highest energy.

Astronomers now know that cosmic rays don't come from all regions of the sky, but they're shot out from actively feeding supermassive black holes.

The exact process that creates the cosmic rays isn't fully understood, but astronomers think that the environment around an active supermassive black hole is ferocious, to say the least. Powerful magnetic fields are generated, which can act like natural particle accelerators, pushing protons to energy levels much higher than anything physicists could recreate with our technology.

Rosetta Is Returning to Earth for Another Flyby


Mark your calendars for November 13th, 2007. That's the day ESA's Rosetta spacecraft will be making a close encounter with Earth on its way to Comet 67/P Churyumov-Gerasimenko. What's going on? The comet's out there guys, why is Rosetta back home? Well, it's all about speed.

Launching spacecraft is an energy intensive business. You can only get a spacecraft going so fast when it launches directly from Earth. But using a technique called gravity assist, spacecraft can use the gravity of a planet - such as the Earth - to get a speed boost. Most of the robotic explorers do it.

In order for Rosetta to make its encounter with Comet 67/P Churyumov-Gerasimenko in 2014, it needs to be going much faster. It already got a gravity assist from Earth back in March 4, 2005, and another with Mars on February 25, 2007. Now its time for a third on November 13. We won't be done with Rosetta yet, either. The spacecraft is due to make a 4th and final flyby on November 13, 2009.

Before it returns for the 4th flyby, Rosetta will swing out across the asteroid belt and observe asteroid Lutetia, testing out its scientific equipment.

Finally, in 2014, Rosetta will reach Comet 67/P Churyumov-Gerasimenko and begin some serious investigations; even landing a probe down on its surface.