30 October 2008

Hubble's Back Up!

As evidenced by the below image!

Interacting Galaxies Arp 147

On the left is what looks nearly like a normal spiral - except that the spiral has been distorted by the interaction into a ring. And also the center is bluer than normal, indicating star formation where usually the core has more older stars and star formation occurs mainly in the spiral arms. To the right is the second interacting galaxy, which is a distorted mess of blue where new stars have been triggered to form from the interaction, and a blob of colder dark gas blocking our view somewhat where it appears reddened.

Outside the Universe?

One of my friends over on LiveJournal asked what's outside the universe. Thought it'd be fun to post my response here and see what y'all think.

The current model of the universe says that there isn't an "outside" to it in that if you keep going in one direction you can "leave" the universe. It's like if you look at a map of the Earth and ask what's past the edge - the Earth is round so you just come back to the other side of it. We're not convinced that our universe is finite in size (and therefore loops back on itself) or if it's instead infinite.

However, when you look at the flat map of the Earth, what that map fails to show is that since the Earth is a sphere, you *can* leave the Earth. If you could leave the universe, our best guess right now (via string theory) is that there are multiple "higher dimensional" universes called branes (short for membranes) that intersect to form universes like ours. So if we had hyperdimensional eyes, we'd see a bunch of sheets that cross each other, and at each crossing is another universe. I'm not sure if this idea is testable yet, or if it's still just a pipe dream though.

29 October 2008

iPhone Astronomy

iPhone-based astrophotography is begun. Below is an image of Jupiter taken by an iPhone through an 8" Meade Cassegrain telescope by amateur astronomer Mike Weasner.

Jupiter with moons and stripes

Note that on the right you can see three of the moons of Jupiter - this is similar to what Galileo saw when looking through his small 2" refracting telescope, hence the four largest moons are dubbed the Galilean moons in his honor. Continued observations of Jupiter over the course of days, months, and even years led Galileo to the realization that they were orbiting Jupiter, not the Earth, and therefore the Earth was not the center of the universe.

Another thing you can see in this image is that the face of Jupiter has bands across it. Galileo could not see these himself, but he saw other "irregularities" or deviations from perfection on the Moon (craters), Saturn (rings, which he couldn't identify as such), and Venus (phases, like we see our Moon go through naked-eye). These other features also helped support Galileo's claim that the universe was NOT perfect, and did NOT revolve around the Earth. Rest assured if he had seen stripes on Jupiter, he would have recorded such a fact.

So this little iPhone image is better than what the father of modern astronomy saw himself.

For more information on this image and the telescope used, see also:
* Bad Astronomy (Dr. Phil Plait)
* The Mac Observer (John Martellaro)
* Weasner's Mighty ETX Site (Mike Weasner)
* Meade Telescopes, LX200-ACF model

28 October 2008

To any Texan readers:

I know there's a couple of you who read me. The Gov of Texas has just appointed a 6-person committee to revamp the state's K-12 science curriculum. One of these six individuals is a creationist. A second person on the committee is not just any ol' creationist, but the director of the US's biggest creationist organization: Stephen C. Meyer, director of the Discovery Institute. And the chair of the committee is Donald McLeroy, who has gone on record as saying that biology textbooks containing evolution are anti-Christian and anti-American.

If you give a shit about this, there's more info on astronomer Phil Plat's blog along w/ more links. Unfortunately the only one who can change this situation is the governor, and he's in power until 2010, but perhaps you guys can make his life a little more difficult.

27 October 2008

Stephen Hawking to retire

Stephen Hawking is facing a mandatory retirement clause at Cambridge University at the end of the year. But we all know that good physicists don't ever quit, they just go emeritus, stop teaching, and do research full time.

19 October 2008

Hubble Update

NASA has started the switchover process to Side B - it turns out I was a bit fuzzy in my understanding before. The two "sides" are not the power source, they're computers that interpret commands from Mission Control, and send data back down to the ground. Either way, Hubble can't take any data while this equipment is down. Because it's actually a computer, and the process of switching from one to the other is complex, they haven't tested Side B since it was launched - why mess with a good thing as long as Side A was working. So during the process of switching over, they hit a snag, though they haven't detailed what the problem is. Time will tell how easily they'll fix it. At the worst, the next Shuttle Servicing (I think it's scheduled for February?) could bring a whole new "side" up and fix the problems.

In the meantime, many astronomers are losing their time on the Hubble. It's my understanding that if you lose your time, you have to reapply for more time in the future, but you tend to get a high priority if that's the case. (This is a similar process to how it works if you're on a land-based telescope and you get clouded out.) There are a few projects that have guaranteed time, and they essentially get a percentage of the functional HST time, so for any time that the HST is down they just lose their time. The people/institutions who "own" that time can choose to reschedule as they wish.

16 October 2008

The tricky question of "what is science?"

Linking here to a third-hand blog post about how scientists often can't define terms like "theory" and "law." No wonder the media gets them mixed up! Part of the problem though is that scientists don't study how they do science, they just do it. Studying how science is done would be part of epistemology (the study of how we know things), which is part of philosophy. It's also in the realm of science education - but unfortunately science educators also don't know how science works... *grumble* No wonder things like ID and the Moon Hoax have managed to make such inroads into our culture!

13 October 2008

IR Photography

This weekend I was playing around with an infrared filter on my digital camera, and realized that the resulting photos could help illustrate some points in astronomy.

Different types of light are important in astronomy, as they are tracers for different processes and temperatures inside the objects we're looking at. Since we can never go to most of the objects we study, it's crucial that we get as much information as we can from light alone. For example, IR light is good for studying cold objects, and for studying objects that are hidden inside a cloud of dust.

Take a look at the three photos below.  They are (in order) normal visible light as our eyes see it, a black and white version of what our eyes normally see (visible light), and an infrared image (displayed in black and white). (Click on the images for bigger versions.)


Notice how in the last image, the water and the sky appear darker. This means that they are not sending as much IR light towards the camera as they are sending visible light. Specifically, this is the same reason as the sky is blue: light from the Sun comes in all colors. Red light (and infrared light) tends to go straight through the Earth's atmosphere. Blue light, however, gets scattered by dust in the air, so as a result the whole sky looks blue. Since the red light goes straight through, this is also why at sunset the Sun looks red. Since the IR light goes straight through as well, when we look at the sky in IR light, we do not see the IR light from the Sun scattered throughout the sky, so the sky looks dark. Lakes look bright blue because the blue light of the sky is then reflected back at our eyes, so in IR lakes and rivers would also appear dark. Note however, that the clouds on the horizon of the IR image do appear bright - the high water content in these clouds does scatter the IR light back towards the camera.

Similarly, IR light goes right through thin clouds in space (just like it goes through our atmosphere), but it does eventually get stopped by thicker clouds (just like the clouds on the horizon in the last image). Because of this, we have to use radio waves to see through the densest clouds. And also because of the clouds and moisture on Earth, we cannot actually do sensitive IR imagery from the ground, and have to instead do it from very high mountaintop observatories (above much of the Earth's atmosphere), or from space telescopes like Spitzer.

05 October 2008

MESSENGER flies by Mercury tonight

MESSENGER, the latest mission to Mercury, makes its second fly-by of the planet tonight. Keep your eyes peeled for articles online with the new pictures in the morning!

Let's see what the astrologers have to say about this one (considering that Mercury's in retrograde, yadda yadda).


This weekend, if you live in more Northern climes, keep your eyes peeled for the Northern lights (or Southern if you live more southerly). As we come more into solar maximum, they should become more common. Aurorae are caused by charged particles from the Sun interacting with the Earth's magnetic field, much like a current in a fluorescent bulb interacts with the ionized gas inside. As we approach solar maximum, the Sun is more likely to throw off loops of material in a solar flare, like in the below picture.

If there is enough material, and it's sent in the right direction (towards Earth), then in a few days it'll get to us and we'll have a chance of Northern lights! Because of how the Earth's magnetic field is shaped, they tend to happen towards the poles, so if you live in Canada chances are you've seen them, and if you live in Florida chances are you never will.