Chris Lintott’s Universe

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.

You can listen in the browser :

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.
* Follow ESO Astronomy on Facebook.

I’ve really missed podcasting since the demise of Living Space’s previous incarnation, and the odd interview just isn’t the same. I’m delighted to say that I’ve managed to cajole the very busy and very knowledgeable Douglas Pierce-Price from ESO, the European Southern Observatory to join me. You can listen to our first show here :

or download it by right clicking here. We’ll have a web site up to go with this shortly, but in the meantime here’s this episode’s show notes.

In today’s show, Chris and Douglas talked about the how the planet Mars has turned out to be colder than expected, how the youngest supernova remnant in our Galaxy has just been discovered, and how astronomers have used a distant quasar and galaxy to take the temperature of the early Universe.

NASA’s Mars Reconnaissance Orbiter finds that Mars is colder than previously thought

Observations made with the Shallow Radar instrument (SHARAD) on the Mars Reconnaissance Orbiter (MRO) have shown that the outer shell of Mars is colder and more rigid that previously thought. SHARAD, which was built for the spacecraft by the Italian Space Agency, uses shallow subsurface radar to search for liquid or frozen water to a depth of about a kilometre in Mars’ crust. By looking through the layer of ice, sand and dust in the Martian north polar cap, the researchers could see through to the surface of the rocky crust underneath. It turns out that the planet’s surface is not sagging under the weight of the icy polar cap (as would happen on Earth), meaning that Mars’ outer shell must be very thick and cold. This result has implications for the search for liquid water hidden beneath the surface (and therefore also possible sites for life on Mars), as any underground aquifers would have to be deeper than previously thought in order for temperatures to be high enough.

NASA satellite finds interior of Mars is colder” press release at NASA.

Youngest Supernova Remnant in our Galaxy discovered

When a massive enough star reaches the end of its life, it can explode as a supernova. Theoretical models suggest that roughly two or three supernovae should happen in our Galaxy every century, but astronomers do not see as many as they would expect. The most recent observation of a supernova in our Galaxy was in 1604, of what is known as “Kepler’s Supernova”, and the youngest known “supernova remnant” - the shell of expanding material following the explosion - had until recently been Cassiopeia A. Observations of Cassiopeia A suggest that its parent supernova would have been observed on the Earth around 1680, but there are no definite historical records of it. Now, astronomers have found a supernova remnant in our Galaxy which has been caught at the new record youngest age of 140 years. The object, called G1.9+0.3, was first identified as a supernova remnant in 1985 by astronomers led by Dave Green from the University of Cambridge, using the Very Large Array (VLA) radio telescope in New Mexico. Then, in 2007, a team led by Stephen Reynolds of North Carolina State University observed the same object with the Chandra X-ray Observatory, and found that it was 16% larger than in 1985. The shell must be expanding very quickly to have grown so much in 22 years, which tells us that it must be very young. Follow-up observations at the VLA confirmed this result, and by looking at the expansion rate the astronomers were able to calculate the record-breaking age of the young supernova remnant. The supernova itself could not have been seen 140 years ago because of obscuring dust towards the centre of the Galaxy, but thanks to radio and X-ray observatories which can penetrate the dust, today’s team were able to find this example of the “missing population” of young supernova remnants.

Youngest stellar explosion in our Galaxy discovered” press release at NRAO.

Using a quasar and a galaxy to take the temperature of the early Universe

Astronomers have used a distant galaxy, and an even more distant quasar, to take the temperature of the early Universe. For the first time, they were able to detect a tell-tale absorption of light by carbon monoxide (CO) molecules in a galaxy so far away that its light has taken 11 billion years to reach us. The observations, made with ESO’s Very Large Telescope (VLT) in Chile, used the light from an even more distant quasar - a galaxy which emits intense radiation powered by a black hole in its core - as a ‘flashlight’ to study the galaxies between the quasar and the Earth. When the quasar’s light passes through each intervening galaxy, molecules in the galaxies absorb specific wavelengths of that light. Due to the expansion of the Universe and of the light itself over these billions of years, each galaxy leaves a fingerprint in the quasar’s light at different wavelengths. In this particular very distant galaxy, the astronomers observed the fingerprint of CO molecules, where the precise levels of absorption depend on their temperature, so the molecules act like a cosmic ‘thermometer’. Today, the Universe is filled with Cosmic Microwave Background radiation at a temperature of 2.725 K (about -270 Celsius). However, according to the Big Bang theory, the Universe was hotter in the past. The theory predicts that the temperature 11 billion years ago would be about 9.3 Kelvin, and the observations of the CO molecules gave a temperature of 9.15 Kelvin, plus or minus 0.7. This is an excellent match with theory, and an exciting new result which shows how interstellar chemistry in the early Universe can be used to tackle big cosmological questions.

A molecular thermometer for the distant Universe” press release at ESO.

Later than I’d like, today’s Living Space is up. We joined Patrick to chew through the latest results from the Moon, and also talk about Mars and Venus Express results.

After what’s possibly the longest summer break in recorded history, Living Space - the podcast I do with Harriet Scott - has relaunched over at Livingspaceonline.com. It’s taken a while to get to this point partly because we were trying to control as much of the process ourselves as possible without compromising on the quality of the sound. I think we’ve managed that, so please do come and catch up. The programme will be fortnightly, and the best way to keep in touch and get the usual mix of interviews and news is to subscribe to our rss feed (this is different from the old feed, so update your bookmarks).

Did I forget to tell you that the latest Living Space was online? And that it contains a fantastic preview of the Phoenix mission to Mars?

Sorry for the delay, but you can still listen to it or download it to save it for ever.

Our latest round up is now available, so go over to Living Space for all that’s new in (and in this case, before) our Universe. Rover expert Doug Ellison of Unmanned Spaceflight brings us up to date with news from Mars, and you should listen to the end to find out what rock music sounds like on Titan.

We’re having some trouble with itunes, so if you normally subscribe to the feed it’ll be quicker to go and get the show yourself today.

I managed to forget to put a link up to this week’s Living Space which features an extended interview with Associate Director of UKIRT, Andy Adamson, and Associate Director of the JCMT, Antonio Chrysostomou (whose name I garbled horribly).

Do go and listen for all the latest from my two favourite telescopes.

This week’s Living Space is now online, featuring news from Jupiter with BAAJupiter section director John Rogers, and a fantastic interview with Stuart Clark. Aside from Patrick, Stuart has had the greatest influence on both my careers and it was fantastic to be able to get him on the show.

Today’s Living Space podcast is now available, featuring an extended interview with astronaut Piers Sellers. It’s worth listening if only to find out the real answer to the old question about what can be seen with the naked eye from space. The answer made me - and everyone I’ve talked to about it - go ‘Wow’.

Tomorrow’s Living Space is the first of our extended interviews, featuring twenty minutes of chat with astronaut Piers Sellers. With the crew of Atlantis struggling with a whole host of problems, what better time to hear about the problems of working in space? Harriet will also have the latest on the current shuttle mission, and you can of course still listen to the two previous episodes (which are up there now).

Thanks to all those who have emailed with comments on the podcasts. All feedback is welcome! If you haven’t gone and listened yet, why not?