Daily Archives: 13/04/2010

Rock and ice at NAM2010

The National Astronomy Meeting 2010 at Glasgow University has been hearing from those interested in water in the universe, according to the Astronomy Now magazine’s NAM2010 blog.

The big story (covered in Discovery as well as Astronomy Now) is on the emergence of pollutants in the atmospheres of White Dwarfs. Now there’s no reason for these to be there as the atmospheres of these things tend to be pretty clean. However, observations show 3-20% have some level of pollutants (the level to which the survey was sensitive to was the mass of a 150km asteroid). Previously, people thought this may be due to stuff lying about between the stars and the telescope in interstellar space, but the analysis of this survey refutes that, suggesting the material comes from the remains of rocky material around the star. In addition the signature of water was detected far and wide, suggesting there are a lot more wet planets out there than thought as well as a lot more rocky ones.

…and the water didn’t stop there. A new class of objects known as Main Belt Comets were presented which were comets residing in the asteroid belt. Now we know comets are closer to frosted blocks of rock than dirty ice, we also know that ice can remain trapped in them for a very long time even part way into the inner solar system. This allows us to look for the signatures of bodies with no frost on the outside that are nevertheless emitting small amounts of ice from pockets below the surface, possibly exposed due to impacts or fragmentation. About a half dozen MBCs have been seen.

A most certainly non MBC was Comet McNaught, which put on a huge show in 2007 with a tail stretching across the horizon. Now results from the Ulysses spacecraft suggest that the extent of the ionised comet was even greater. The spacecraft measured the wake of the comet in the solar wind from a distance more than one and a half times the Earth Sun distance away. It took the spacecraft eighteen days to cross the wake, compared with 2.5 days for Comet Hyakutake. Of course, things like the increased width of the wake with distance and the strength of the solar wind encountered do need to be taken into account, but measurements from other spacecraft such as Giotto, which encountered the tails of Grigg-Skjellerup and Halley, each taking a matter of hours to cross, seem to confirm the immensity of McNaught’s plasma presence.

Another thing revealed in that session was water in lots of exoplanetary atmospheres. In other sessions, more exoplanets popped up – nine new ones to be exact. The nine new planets included some with backward orbits and strange inclinations. The suggestion from these is that they didn’t simply migrate inwards of their own accord after forming from the protoplanetary disc, but were kicked in by gravitational interactions with say a nearby brown or red dwarf. The bad news is for Earth like planets in the vicinity, migration is something that can be coped with, huge planets bouncing round like deranged comets looking for a fight is not. Earths in this situation are either destroyed or depart the planetary system, looking to be alone.

Astronomy Now also recorded a few interviews at NAM2010 and stuck them on their youtube channel:

Meanwhile, UCL released a mini-lecture by one of its PhD students on the science her group is doing on the moons of Saturn.


The policies are shining through – where’s the science?

The Labour and Conservative party manifestos for the 2010 general election are out (Lib Dems tomorrow). A brief summary of their commitments and otherwise to science is given in the Times. A more in depth look for #SciVote is given here for Labour and here for the Conservatives and a summary of the two here and here. As the Times says, they’re pretty much interchangeable.

The Guardian has an article on the rise of science in popular culture, including several celebrities with interests in science.

Solar explosions seen

Now that the Sun has become more active again, lots more prominences and Coronal Mass Ejections are being seen (not least the ones that keep smacking into us).

On the 3rd of April, the STEREO spacecraft captured this movie of an eruption.

Meanwhile, today SoHO captured this image of a series of events summarised in this movie.

Of course, you don’t need a satellite to see something like this – a good filter or a solar telescope will do the job nicely, as proven in this image by Richard Bailey, director of the solar observing section in the Society for Popular Astronomy.

More possible auroral activity

The Earth has been hit by another CME (I know, we seem to have a target painted on us at the moment) potentially sparking off more auroral activity (as with the last one, it hit when Australia was in darkness, so New Zealand got the southern lights on full beam) according to spaceweather.com. It seems to have died down a lot, and I’ve seen nothing from here, but for the next few nights, keep watching the north for those lights.

But what are the Coronal Mass Ejections and what powers them? One theory involves flux ropes, tight groups of magnetic pathways holding in plasma. The flux ropes form when individual flux tubes (field lines of the magnetic field on which plasma is trapped) get wound together into one structure. One very energetic structure that is held in place as long as the magnetic field outside of it can. Then it bursts into life, shoveling out vast amounts of high density, hot, fast plasma into space. The Hinode satellite has been observing this phenomenon and found flux ropes wound in 30% of the local magnetic field, rather than the 10% previously assumed.

At the other end of the scale, the Cluster satellite has been observing auroral events. The four spacecraft were positioned in such a way as to measure particle energies at different points on a single field line. By looking at how the energies changed with position, the acceleration of the electrons could be directly observed.

More #SciVote stuff

…or stuff of relevance to the #SciVote campaign, which lobbies for improvements in science policy.

David Cameron has responded to #SciVote’s letter to the leaders. But they haven’t put it up on the blog yet (they’re waiting for the others, I guess).

In the Times, there’s two interesting blog posts, one summing up the events in Science Question Time and how to help spread the seed of Science in the UK and there’s one on the problems facing science teachers.

From the comments in the first of those, I noted a blog and a wiki that perform a function I suggested in a blog post here would be a good idea for someone to do not so long ago (they were already doing it, I didn’t know), which is to question every single candidate for the election on science issues.

Now I just need to find someone whose producing leaflets based on those answers…

Some NAM2010 stuff

The 2010 National Astronomy Meeting at Glasgow University, as with every big astrophysical conference, means there’s a steady stream of astronomy stories coming out this week. Will Gater of the Sky at Night magazine is there and has a list of other people who will be tweeting from there. Astronomy Now magazine has been keeping a NAM2010 blog, so here’s a quick summary of today’s science entries in there:

The big pretty picture was the release of a Herschel Infrared Space Telescope view of the Rosette Nebula. The nebula lies 5,000 light years from the Earth and is associated with a cloud of gas and dust with the mass of 10,000 Suns. The giant cloud is a birthing ground for giant OB class stars, the brightest and hottest around. When we look at other galaxies, most of the light we see are due to these stars, as others are too faint to contribute much, so understanding their evolution is a key factor in the Herschel mission. The image is a combination of views at wavelengths of 70, 160 and 250 microns, all invisible to the naked eye and equivalent to temperatures just a few tens above absolute zero. The image was taken as part of HOBYs, a survey of OB stars by the telescope.

Meanwhile, the European Space Agency is presently involved in 17 missions and has to chose two out of four potential missions to fly next.

More for the anniversaries

As I nearly correctly mentioned in the last post, it is the 29th anniversary of STS-1, the first shuttle mission, the 40th anniversary of the time “Houston, we’ve got a problem” was called out and the 49th anniversary of the day Yuri Gagarin went for a wander in a capsule.

Celebrations of Yuri’s Night or Cosmonaut Day have taken place across the surface of the globe and also on the International Space Station. The ISS received a call from the Russian President Medvedev.

The Sky at Night Magazine celebrates by putting a disc on its cover containing archive footage and a half hour documentary on the events of Apollo 13.

Meanwhile, Mission Commander Jim Lovell has spoken to the BBC about his memories of those days four decades ago.