It turns out that it’s hard to launch a new shiny website while traveling through four airports and three countries in the space of less than 15 hours. With apologies to my talented co-presenter, Douglas Pierce-Price from ESO, I’m going to post our latest Living Space here.
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or download the show by right-clicking here.
In today’s show, Chris and Douglas talked about the American Astronomical Society meeting in St Louis, Missouri (where Chris had just heard the reports of the lowest mass exoplanet discovered so far – a three Earth-mass frozen planet orbiting a brown dwarf), the latest news from the Phoenix lander currently on the surface of Mars, and how a stroke of luck let astronomers catch a supernova in the act. They also celebrated the 10th anniversary of the First Light of the Very Large Telescope (VLT).
Phoenix lander starts work on Mars
The Phoenix lander has successfully landed in the northern polar region of Mars, on its mission to search for ice, study the history of water in the Martian arctic, and look for a habitable zone where life might have arisen. We admired the images from the Mars Reconnaissance Orbiter, showing Phoenix on its descent, and sitting safely on the Martian surface.
The lander is now beginning its work, and one of the first things it did was to use its robotic arm camera to look underneath itself. This revealed what appears to be ice, a few centimetres under the surface, uncovered by the blast from the descent thrusters. Phoenix is in a flat, frozen region of the planet, where polygonal patterns can be seen on the surface. These polygons are probably caused by cracks from the repeated shrinking and expansion of permafrost ice, and similar effects can be seen on Earth. The troughs around the polygons could be a good place for Phoenix to dig and study the Martian soil.
The mission scientists have a limited amount of time to do their work and get their results: once the Martian winter night arrives in a few months, Phoenix will not be able to use its solar cells for power, and it is not expected to survive the cold and ice. Before then, though, we look forward to lots of exciting results from Mars!
* Mars Live coverage of the Phoenix mission
* Phoenix Mars Mission home page at the University of Arizona.
A supernova caught in the act
When a sufficiently massive star reaches the end of its life and runs out of nuclear fuel to burn, its core can collapse. This collapsing core then rebounds, and the shockwave blasts the star’s outer layers apart in a powerful explosion known as a supernova. We normally only detect supernovae when their visible light starts to increase, days after the shockwave. Theoretical models suggest that the initial blast itself should be accompanied by a flash of X-rays lasting a few minutes. However, such a short flash is hard to detect unless one is looking in the right direction at the right time. You’d have to have amazing luck to catch one.
That’s exactly what happened to a team led by Alicia Soderberg, who were using the X-ray telescope on the satellite Swift to study an existing supernova in the galaxy NGC 2770. Suddenly, they discovered a bright, completely new source of X-rays in the galaxy. Ground-based observatories quickly mobilised to study the event, which was confirmed to be a supernova caused by the core collapse of a massive star. This is the first time that a supernova has been caught in the act like this, and the observations will provide a treasure trove of information about these incredible explosions.
* “Birth of a supernova” press kit at Princeton University (with press releases from other institutions)
* Swift mission home page at NASA
Tenth anniversary of First Light at the Very Large Telescope
ESO’s Very Large Telescope (VLT) is celebrating the tenth anniversary of its “First Light”. The telescope’s First Light occurred during the night of 25-26 May 1998, and the first images were released on 27 May 1998. The VLT, on Cerro Paranal in Chile, is the world’s most advanced optical/infrared observatory, with four giant 8.2-metre diameter “Unit Telescopes” and four 1.8-metre diameter movable “Auxiliary Telescopes”, which can be combined together into the “VLT Interferometer” for improved resolution.
One of the First Light images was of the giant star Eta Carinae and its surrounding cloud of dust and gas, which was taken with a test “guide camera”. Now, to mark the anniversary, two new images have been released, including a new one of Eta Carinae, this time taken with the advanced Adaptive Optics instrument NACO. Thanks to the power of Adaptive Optics, which corrects for the distorting effects of the Earth’s atmosphere as though the telescope were up in space, the new image has six or seven times better resolution and reveals even more details.
Over the last decade, the VLT has been responsible for a series of fantastic scientific results, including observations of a star orbiting extremely close to the supermassive black hole in the centre of our Milky Way Galaxy. This is, of course, just the beginning. With the second generation of advanced instruments for the VLT on its way, astronomers can look forward to the next decade of exciting discoveries.
* VLT First Light 10th Anniversary press release at ESO.
* 10th anniversary images, including Eta Carinae, at ESO.
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