Monthly Archives: June 2009

Download Nasa mission posters and factsheets

Like movie posters (indeed, in many cases based on them), Nasa Mission Posters are designed to entice viewers and display the stars, so to speak, of the show.

Nasa have a webpage that includes a series of these posters as well as factsheets and a slide show for the 25th anniversary of the space shuttle. To view and download these, click here.

Blobs reveal black hole formation

via Nasa.

Lyman Alpha blobs are enormous concentrations of hydrogen gas that are emitting light at the wavelength known as Lyman Alpha. Dozens of blobs, each hundreds of thousands of light years across and at a distance equivalent to when the Universe was a mere two billion years old, are known to dot the skies, but where do these giants come from?

Nasa studied 29 lyman alpha blobs with a series of different telescopes, both on the Earth and in space. The Earth bound Japanese telescope Subaru, located in Hawaii, took images of the blobs themselves. In the image below, these are shown in yellow. The Hubble and Spitzer space telescopes took images of galaxies in the area – Hubble’s optical data are in white, Spitzer’s infrared data are in red. Finally the Chandra space telescope took some x-ray images that are likely to trace high energy events such as accretion around black holes. These are coloured blue.

Credits: Left panel: X-ray (NASA/CXC/Durham Univ./D.Alexander et al.); Optical (NASA/ESA/STScI/IoA/S.Chapman et al.); Lyman-alpha Optical (NAOJ/ Subaru/Tohoku Univ./T.Hayashino et al.); Infrared (NASA/JPL-Caltech/ Durham Univ./J.Geach et al.); Right, Illustration: NASA/CXC/M.Weiss

Credits: Left panel: X-ray (NASA/CXC/Durham Univ./D.Alexander et al.); Optical (NASA/ESA/STScI/IoA/S.Chapman et al.); Lyman-alpha Optical (NAOJ/ Subaru/Tohoku Univ./T.Hayashino et al.); Infrared (NASA/JPL-Caltech/ Durham Univ./J.Geach et al.); Right, Illustration: NASA/CXC/M.Weiss

At an age of around two billion years, some of the earliest galaxies were formed through gravitational collapse. The massive amount of hydrogen available after the big bang fell into clumps. As it did so, the release of gravitational potential energy created heat, which can then be emitted as radiation. However, the stuff seen in the picture blob isn’t doing that. At a later stage, hydrogen has fallen into the galaxy, allowing the creation and relatively swift destruction of massive stars, which in turn provides black holes. The central back hole of the galaxy then starts to grow in size, accreting material as it does so. This generates heat and radiation that then pushes hydrogen out, heating it once again. This is the stage at which the vast sheets of hydrogen glow so brightly they that they can be seen from Earth.

Tweetup with Nasa and STS-125

Do you twitter? Twitter is a website where people exchange messages of 140 characters or less. I twitter and use it as a feed reader – ie I get snippets of news through it with links to full stories, which can then be processed on here. Nasa also twitters and would like to meet up with others who twitter.

The forthcoming mission to the International Space Station will see the space shuttle Endeavour blast off on mission STS-127. On the previous shuttle mission, STS-125 or the Hubble Servicing Mission 4, an astronaut sent back tweets to Nasa, which were then put on his twitter account. A similar thing will be done on this mission, hence the Nasa interest in the website.

The astronauts and other behind the scenes participants in the STS-125/HSM4 mission will be in Washington on the 21st of July and wish to “tweet up” with a few “tweeps” or people who twitter… If you want to be one of the 190 twitterers to be involved in this meeting, then go to This Website at 10am EDT on the 1st of July and submit your name. You will need valid government issued ID to get into the building on the 21st.

Take a tour of the ISS

We’ve all seen the ISS drifting over us (haven’t you? Well click on heavens above to get times if the ISS happens to be in your area. If not, then wait and check again in a couple of weeks – or explore other satellites shown on the site). Now Nasa have released a high definition tour of the inside of the International Space Station as it is now.

LRO Mission control

Nasa have released a video of the scenes at Mission Control as the Lunar Reconnaissance Orbiter successfully slowed down and was captured by the gravity of the Moon. Had it not slowed down, it would’ve either passed by or hit the Moon. Had it slowed down too much, the Moon would’ve passed by leaving a slowly drifting probe desolate and alone.

Planetary puppy fat

via New Scientist.

Jupiter is big. The largest planet in our solar system, a huge ball of gas so much larger than our planet it is incomprehensible. But the thing is, in the past Jupiter was bigger.

Gas giants form from the protoplanetary disc like all the rest of the planets. They each retain a little heat from when the disc was warmed by the star and from the release of gravitational potential energy as the gas and dust that formed them collapsed into a planetary heap – the gravity accelerated every particle so it smashed into and heated the young planet. Now gas plus heat equals expansion, and for this reason gas giants are bigger when they are young and haven’t quite cooled down to the temperature expected from the heat they generate through sporadic fusion, fission of heavier elements and the receipt of energy through solar radiation, the aurorae and tidal interactions with their moons.

However, some older gas giants still seem to retain their puppy fat, most notably some exoplanets, some of which are a good 30% larger than expected. Laurent Ibgui of Princeton University recently calculated that these planets may be able to retain their size by having elliptical orbits – causing tidal interactions with their host star. The side of the planet closer to the star is attracted more strongly than the other side through gravity. The closer to the star the planet is, the greater the stretching. The effect is over the course of an elliptical orbit, the planet is stretched and squeezed and so warmed.

Unfortunately, whilst the calculation makes an interesting contribution to the mystery of the expanded planets, it introduces a new mystery – how do they start off on such a highly elliptical (very eccentric) orbit to begin with?

Mars rover updates

Universe Today has some interesting videos on the Mars Exploration Rovers, Spirit and Opportunity.

Spirit is still sadly trapped in the Martian regolith as engineers back on Earth try to work out how to free the thing. Its solar panels on the other hand received another wind assisted cleaning and are now generating so much power there is a hint that they may try to take images of the Martian night.

Opportunity on the other hand continues its long trek south towards Endeavour crater. There is an indication that things may be starting to decay on that rover too as the drive was temporarily halted due to too much current being fed to the front right wheel. The situation was assessed and the problem recognised. The rover was put in reverse for a while, but that doesn’t seem to have helped, so more analysis of the ‘actuators’ is ongoing to determine why that wheel is drawing so much juice.