Stunning pictures of the Sun

NASA’s Solar Dynamics Observatory – launched into space on February 11 – has sent back some amazing images of our Sun. Click here for several series of animated images that show flares, eruptions, and thermal currents, captured in spectra we can’t see with our own eyes. The Sun is an incredibly dynamic furnace is the sky, and is constantly churning and flaring and bubbling away up there.

Prospects for extraterrestrial life: there are a lot of rocky planets out there

ScienceDaily has an article that explains why the prospects for the existence of other life in our galaxy just got a bit better.

In brief:

  1. We believe that planets that are mostly “rocky” (as opposed to gas giants like Jupiter and Saturn) and have water are the places where we’re most likely to find other life in the universe. This is because the only planet we yet know to contain life – our own Earth – is like this.
  2. Although we’re discovering more planets all the time most of them are extremely small and far away, so it’s slow going. Spotting stars – because they’re bigger and give off lots of radiation – is much easier.
  3. We’ve now seen that lots of white dwarf stars – which is the final stage of most normal stars (our Sun is one of those stars) – contain significant traces of heavy “rocky” elements and water. This implies that the systems around those stars once had rocky planets and water. That means such systems are quite common. And that boosts the chances that there’s life out there.

From the article:

Dr Farihi comments: “In our own Solar System with at least one watery, habitable planet, the asteroid belt — the leftover building blocks of the terrestrial planets — is several percent water by mass. From our study of white dwarfs, it appears there are basic similarities found among asteroid-like objects around other stars; hence it is likely a fraction of these white dwarfs once harbored watery planets, and possibly life.”

Does Our Universe Live Inside a Wormhole?

Science magazine is reporting a new paper from Indiana University’s Nikodem Poplawski that speculates about whether our universe might exist in a wormhole between two other universes.

Poplawski thinks this idea is worth speculation because it provides possible explanations (or, at least, gives us room to manoeuvre) on two current problems: the unification of gravity with the nuclear and electromagnetic forces, and dark energy.

It all sounds like a bit of a stretch, an attempt to come up with scenarios that fit the facts. But that is one way discoveries are made.

Northern and Southern Lights observed on Saturn at the same time

I’m going to start with some of the fundamentals on this one, and build towards the titular observation.

Everyone’s familiar with magnets. I’m not, in this post, going to drill down into the Standard Model view of electromagnetism; let’s just go with what we know, that some things – like iron – can produce strong magnetic fields.

The Earth is one of those things that produces a magnetic field. It has one mostly because of the molten metal that’s moving around beneath the surface. The Earth ends up being pretty close to a magnetic dipole, like one of those bar magnets you played with in science class in school, so named because it has a north and south pole (that is, its field has an orientation, and each “end” of the magnetic field acts differently). The Earth’s like that too, with two concentrations of the magnetic field lines all collecting at places somewhat close-ish to the geographic north and south poles.

At the same time we’ve got the Sun producing something called the solar wind. That’s the name given to the constant stream of charged particles – electrons and protons, mostly – that are streaming away from the Sun all the time. They’re coming at the Earth, and everything else in the solar system, all the time. Those particles are affected by magnetic fields, though. If they come close to the Earth’s magnetic poles, the shape and strength of the field in those spots can be just enough pull them into our atmosphere. If they do, and the particles smash into oxygen and nitrogen atoms in our air, they can combine and give off a flash of energy that may manifest itself as visible light. That is what we call the Northern (or Southern) Lights, or the aurora borealis(or australis).

But many planets have a magnetic field, and the solar wind blows everywhere, so it’s not just our planet that has these aurora. Saturn has them too, but we weren’t able to see them until 1997. This is because when the charged particles from the solar wind get caught in Saturn’s magnetic field they slam into different atoms, and the flash of energy they give off isn’t visible light, but ultraviolet light of a frequency that gets absorbed in our atmosphere. The first time Saturn’s aurorae were seen was from the Hubble telescope (which, because it’s in space outside our atmosphere, can see that UV light).

Last year, however, Saturn was in just the right spot that its rings and equator were edge-on from our point of view. This meant that we could see the aurorae of both poles at the same time. In doing so we were able to detectdifferences in the north and south aurora. These observations may help us understand the aurora phenomenon, the solar wind, and the internal structure of Saturn.

Here’s a short video of the Hubble images of both aurorae at once.

Or you can click through to this Guardian Science article that has a longer and more detailed explanation from NASA.

Boat could explore Saturn moon

From the BBC:

A daring proposal to try to put a “boat” down on a sea of Saturn’s moon Titan is about to be submitted to Nasa.

The scientific team behind the idea is targeting Ligeia Mare, a vast body of liquid methane sited in the high north of Saturn’s largest moon.

The concept will be suggested to the US space agency for one of its future mission opportunities that will test a novel power system.

It would be the first exploration of a planetary sea beyond Earth.

They put “boat” in quotes like they don’t really mean a boat, but they do. A boat is a vessel that rides the boundary between two fluids of greatly different density, so this explorer would definitely be a boat.

Why do we care about methane lakes on Titan?

According to team-member Dr Ralph Lorenz, what we learn from Titan’s lakes could be relevant here on Earth.

It would give scientists the opportunity to study shared climate processes at work under very different conditions.

“If we have models that will work on Earth and on Titan then we can be much more confident that those models understand the fundamentals of what’s going on,” explained the researcher from the Johns Hopkins University Applied Physics Laboratory.

“The photogenic appeal and the mystique of exploring a sea on another world speak for themselves, but there is a genuine practical application to do with the science that will help us address problems here on Earth.”

Getting a clearer view of supermassive black holes at the centres of galaxies

Most people have heard of black holes: when a big chunk of matter (like a star) no longer has sufficient internal pressure to withstand its own gravity it can collapse and suck in anything that comes past a line called its event horizon. They’re weird, freaky things, to be sure, but theory predicted them, and astronomy has found enough evidence that it’s treated as certain that we can see a bunch of them out there.

Supermassive black holes – in addition to being a great song by Muse – are enormous black holes thought to exist at the centre of most, if not all, galaxies. There are signs of them, and a few models for how they might form.

Scientists have recently been able to better see what’s happening at the edge of some of these supermassive black holes. They’ve done this by cleverly using two nearby telescopes, the Keck telescopes in Hawaii. This technique, called interferometry, allows them to remove the effects of the stuff – much of which is creating a lot of radiation “noise” – that’s happening nearby.

Keck Telescopes. Photo from domesticat via Creative Commons license

Probe slams into Moon, looking for evidence of ice

For the last 113 days Nasa’s Lunar Crater Observation and Sensing Satellite(LCROSS) spacecraft has been traveling towards the moon. Its mission is to find out whether there might be some traces of water buried under the dirt of some of the craters that dapple the Moon’s surface.

At a distance of 54,000 miles LCROSS separated from the rocket that had propelled it from Earth to Moon. The rocket hurted downwards and slammed into the Moon’s surface, sending up a cloud of dust and rocks (and, possibly, frozen ice particles). LCROSS’s instruments observed and recorded this aftermath of the impact, then a few minutes later itself plowed into the Moon.

It’ll take weeks to analyse all the data LCROSS took and sent back. But it looks like a good result so far with just the sort of data capture they were hoping for, with the plume of dust spotted by the sister-mission Lunar Reconnaissance Orbiter (LRO).

Read all about it on ScienceDaily.

Illustration of LCROSS

Illustration of LCROSS