Today is the anniversary of Carl Sagan's death back in 1996. For those of us who have dedicated our professional lives to communicating astronomy to the general public, we owe him a great deal of gratitude. After all, it was Carl Sagan who helped make astronomy accessible for everyone -- and emphasized the importance of doing so. His books, TV series, and public appearances really helped galvanize the public's interest in what lies beyond planet Earth.
Today, astronomy has many telescopes and observatories working to study the cosmos. And, most of these major facilities have education and public outreach offices – including Chandra – to help disseminate these results. We are thankful that those who came before us, like Carl Sagan, who helped paved the way for the work we are able to do.
-Megan Watzke, CXC
This two-panel graphic contains two composite images of galaxies used in a recent study of supermassive black holes. In each of the galaxies, data from NASA's Chandra X-ray Observatory are blue, and optical data from the Sloan Digital Sky survey are shown in red, yellow and white. The galaxy on the left, Abell 644, is in the center of a galaxy cluster that lies about 920 million light years from Earth. On the right is an isolated, or "field," galaxy named SDSS J1021+1312, which is located about 1.1 billion light years away. At the center of both of these galaxies is a growing supermassive black hole, called an active galactic nucleus (AGN) by astronomers, which is pulling in large quantities of gas.
With the seeming time warp of the holiday season upon us, we decided to look up the answer to a question submitted by a Chandra visitor some time ago on the relationship of time and gravity. (Disclaimer: you may not use this text as an excuse to why you forgot to get your 'favorite' relative a gift this year. That's on you - not Einstein.)
Why is time influenced by gravity?
Einstein's theory of relativity showed that space and time are not independent. One consequence of this is that time can appear to pass more rapidly or slowly for two different observers depending on their relative velocities and acceleration. According to the theory of relativity, acceleration and gravity are equivalent, so gravity can affect the flow of time.
This colorful creation was made by combining data from two of NASA's Great Observatories. Optical data of SNR 0509-67.5 and its accompanying star field, taken with the Hubble Space Telescope, are composited with X-ray energies from the Chandra X-ray Observatory. The result shows soft green and blue hues of heated material from the X-ray data surrounded by the glowing pink optical shell which shows the ambient gas being shocked by the expanding blast wave from the supernova. Ripples in the shell's appearance coincide with brighter areas of the X-ray data.
This composite image shows an intergalactic "weather map" around the elliptical galaxy NGC 5813, the dominant central galaxy in a galaxy group located about 105 million light years away from Earth. Just like a weather map for a local forecast on Earth, the colored circle depicts variations in temperature across a region. This particular map presents the range of temperature in a region of space as observed by NASA's Chandra X-ray Observatory, with the hotter temperatures shown in red and decreasingly cooler temperatures shown in orange, yellow, green, and blue. The numbers displayed when rolling your mouse over the image give the gas temperature in millions of degrees.
Jonathan Taylor, Senior Lecturer in Creative Writing at De Montfort University in the UK, wrote two poems called 'History Lesson' and 'Black Hole in B-Flat,' both inspired by Chandra discoveries, and featured on Chandra's blog. Because of the success of these poems, Chandra and De Montfort University subsequently ran a competition for Creative Writing undergraduate students, in which they were invited to submit poems inspired by one of Chandra's press releases. The competition aimed to uncover the poetry inherent in the kind of scientific discovery undertaken by Chandra, and the four winning entries certainly succeeded in doing precisely that.
Here are the third and fourth placegetters in the competition. The first and second placegetters will be included in a future blog posting.
There have been many odes and tributes to Chandra over its 11-year run so far, but here's one that we certainly never expected: Chandra immortalized in petroglyphs. The artist, Kevin Sudeith, carved an image of the spacecraft into rocks alongside a road in Montana. While we hope that Chandra lasts a very long time, it is certain that this tribute to the telescope will last even longer. So thanks to Kevin for his excellent art and his devoted interest in Chandra.
-Megan Watzke, CXC
This composite image shows a supernova within the galaxy M100 that may contain the youngest known black hole in our cosmic neighborhood. In this image, Chandra's X-rays are colored gold, while optical data from ESO's Very Large Telescope are shown in yellow-white and blue, and infrared data from Spitzer are red. The location of the supernova, known as SN 1979C, is labeled (roll your mouse over the image above).
Today, Google is marking the 115th anniversary of the discovery of X-rays by William Roentgen, a German physicist. Here at the Chandra blog, we are not sure if this exact date is the most important one, but we do know that he made his discovery some time during 1895. And, hey, we are always in the mood for a little celebration of all things high-energy.
The last time I wrote a blog entry on the Sun was about two months ago. I noted that although the Sun had an outburst in August it was still fairly quiet. It remains fairly quite, although the sunspot numbers have been steadily creeping up for the last few months and there were four weak "C-class" flares last week. The observed rates are still only about two-thirds of the predicted values.
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