Astronomers Tackle 400-Year-Old Mystery

[zavvy]

Astronomers Tackle 400-Year-Old Mystery<br /><br />LINK<br /><br />On the night of October 9, 1604, sky watchers – including Johannes Kepler, an astronomer best known for discovering the laws of planetary motion – were startled by the sudden appearance in the western sky of a "new star" which rivaled the brilliance of the nearby planets. Now, exactly 400 years later, a pair of astronomers at The Johns Hopkins University is using NASA's three Great Observatories to unravel still-mysterious aspects of the remains of this supernova, the last such object seen to explode in our Milky Way galaxy. <br /><br />When this bright object – now called "Kepler's supernova remnant" – appeared alongside Jupiter, Mars, and Saturn on that long-ago October evening, observers had only their naked eyes with which to study it because the telescope would not be invented for another four years. Johns Hopkins University astronomers Ravi Sankrit and William P. Blair, however, have the combined abilities of the Spitzer Space Telescope, the Hubble Space Telescope, and the Chandra X-ray Observatory at their disposal, and are using them to analyze the continuously expanding supernova remnant's appearance three ways: in infrared radiation, visible light and X-rays. <br /><br />"Multi wavelength studies are absolutely essential for putting together a complete picture of how supernova remnants evolve," said Sankrit, an associate research scientist in the Center for Astrophysical Sciences at Johns Hopkins University's Krieger School of Arts and Sciences and the lead astronomer on the Hubble observations. <br /><br />"The glow from young remnants, such as Kepler's supernova remnant, comes from several components," he said. "Each component shows up best at different wavelengths." <br /><br />The resulting combined image unveils a bubble-shaped shroud of gas and dust that is 14 light-years wide and is expanding at 4 millio

 

[newtonian]

zavvy- Thank you for the link - a few of the amazing photos of the wonders of our universe!<br /><br />Now, the supernova remnants are said to be expanding at 4 million miles per hour. Yet the original explosion is said to cause a shock wave moving at 22 million miles per hour.<br /><br />How can this be reconciled? Is the outer layer in the photo the shock wave with its accompanying gas swept with it, and the inner glowing gasses the slower expanding supernova remnants?<br /><br />If not, how could it slow down that much in just 400 years???<br /><br />I really don't understand how the ejecta can catch up to the shock wave, as your link states:<br /><br />"The material from the explosion called "ejecta" initially trails behind the shock wave but eventually catches up with the inner edge of the shell and is heated to X-ray temperatures."<br /><br />How does it catch up????