If you’re wondering what all the buzz has been about the past few days over a NASA discovery, then wait no longer. No, it’s not aliens or an incoming asteroid. Instead, it’s still very cool: astronomers have found the youngest supernova in the Milky Way.

First, before I explain, here’s the photo of the newest galactic family member:

It kind of looks like a baby head swaddled in a blanket. Or a really bad drawing of Caesar. Anyway, seriously, this is a big deal. Why?

When a star like the Sun dies, it blows off a lot of its outer layers, leaving behind a dense hot object called a white dwarf (FYI, I have a more detailed description of all this here). If the star is binary — it has a companion — then the immense gravity of the white dwarf can draw material off its mate, and that matter will pile up on the surface of the dwarf. If enough piles up at just the right rate, it can ignite in a thermonuclear fire. This sets off a chain reaction, and the entire star self-destructs. This creates an immense amount of energy — as much energy is released every second as the Sun emits for billions of years — and an octillion tons of gas is launched violently into space at a large fraction of the speed of light.

The event is so titanic that it can be seen clear across the Universe, and of course you don’t want one to happen too close^*. But somewhat close is good: we can study them better.

We know how many stars like this there are in our galaxy (as well as massive stars which can also explode, although using a different mechanism), and we know roughly how long they live, so we should be able to predict how often one should go off. The answer is, about three per century, more or less.

But observationally, it’s been more less than more. That is, the last one we know of that blew up in the galaxy was over 400 years ago. That’s been a major pain for astronomers; statistically speaking, it’s a little weird that we haven’t seen one since the 1600s.

But that’s changed. After searching for literally decades, astronomers have found a supernova in our galaxy! It’s official name is G1.9+0.3, which doesn’t exactly make your heart sing, I know. But it’s very cool. It’s a remnant, the expanding gaseous debris from a supernova blast. It’s located very near the center of the galaxy, about 28,000 light years away, and it’s only at most about 140 years old.

The false-color image above shows the remnant as seen by the orbiting Chandra X-Ray Observatory, and the ground-based Very Large (radio) Array in New Mexico. To give you a sense of scale, the object is about 13 light years across, or 80 trillion miles end-to-end. The orange crinkly stuff is extremely hot — millions of degrees hot — X-ray emitting gas, generated by vast magnetic fields in the gas. The bluer material is smoother radio wave emission also dominated by magnetic forces.

Together, they paint an interesting picture of this explosion. For one thing, it looks like a ring, or a smoke bubble. That’s a clear sign that it’s actually a shell of material, and not a solid sphere. A filled sphere of gas would be brightest in the middle and fainter near the edges (because we’re seeing more bright material when we look through the center of a sphere as opposed to near the edge), but a shell has the opposite behavior.

For another, it’s asymmetric: the gas is not expanding in a perfect sphere. Either it’s slamming into gas that existed outside the star before it blew up, or the explosion wasn’t perfectly spherical. That tells astronomers quite a bit about the physics of the explosion mechanism.

How do we know it’s young? Ah, an excellent question! I love this part: we’ve seen this sucker expand!

Here are two radio images of the remnant taken 23 years apart:

See how it’s gotten bigger over time? By measuring that expansion and knowing the time elapsed between the two pictures, we can extrapolate backwards to see how old the object is. If you do the math, all that gas was in one point about 140 +/- 30 years ago. That’s actually an upper limit to the age: it may have been less than that, if the expansion is slowing over time due to the material slamming into gas floating in space. That’s likely; that region of the galaxy is pretty thick with dust and gas.

In other words, this thing went off around the time of the American Civil War.

So that’s how we know it’s the youngest we’ve ever seen. But there’s more! We know the distance to the remnant as well. The amount of dust and gas between us and it can be measured and compared to known maps of the galaxy, kind of like knowing how far away distant mountains are by the amount of haziness you see between you and them. Combining the distance with the expansion measured means we can get a real velocity for the gas, and it’s a whopper: 14,000 kilometers per second, or 5% the speed of light! That’s fast. The amount of energy released in a supernova is numbing.

So you may also ask, why didn’t anyone see this thing when it went off? All things being equal, at that distance it should have been as bright as Venus in our skies, visible even in daylight! But all things are not equal: all the gas and dust between us and it absorb visible light, making this object almost totally invisible. It might have been visible to someone using a good telescope a century or more ago when the explosion took place, but that astronomer would have had to have been looking at just the right spot, and noticed a very faint star that wasn’t there a few weeks before — and this object sits in a part of the sky loaded with faint stars. It would be like noticing a new grain of sand on the beach. Unlikely, and in fact no one did notice.

It can be seen now because we have more advanced instruments these days. X-rays and radio waves are not as affected by intervening glop in the galaxy, and pass right on through. That’s why we can see it at all; even in big optical telescopes G1.9+0.3 is totally invisible.

So there you go. This object will be heavily studied now, I’m sure, because it’s the youngest such explosion we can see up close. It may help us understand how white dwarfs explode, and what the environment is like near the center of the galaxy, and how gas behaves when it violently expands in such a place.

And, well, it’s just cool. It’s been a mystery for a long time why we haven’t seen any young remnants — we expect there to be 60 of them younger than 2000 years, but only 10 are known — and now that we’ve seen this one we know they’re out there, but really just a pain to detect. You can bet that astronomers will look even harder for more of them now that we know they exist.

Emily Lakdawalla, the blogger for The Planetary Society, has learned from the master. She will be hosting a live video chat Wednesday May 14 (tomorrow) at 3:00 p.m. Pacific time (22:00 UT) on her UStream channel. You can get more info on her blog.

I’ll be there in the chat room, and I urge everyone else to take a look too. Emily is very knowledgeable and very funny, so I’m sure this’ll be a good way to spend an afternoon.

While poking around the intertoobs a few days ago, I found a remarkable blog by a young woman. She volunteers at the Denver Museum of Science and Nature, an excellent place where you can learn all about reality (and where "my" black hole show was created).

Sadly, this young woman also sees creationists giving tours and lying about said reality. Her blog post on this subject is truly worth reading. It would be considered well-written and thoughtful by anyone.

So imagine my surprise when I found out, coincidentally just now, that she’s only 14 15.

Fourteen! Fifteen! Amazing. I foresee a very bright future ahead of this young lady.

Just some stuff I get in email and from other sources… read these all the way through. You’ll love #6.

1) 85% of Americans wants a Presidential debate on science. I do too, if only for the hilarity factor. I’d love to see Clinton questioned repeatedly on how little she trusts experts.

2) The SciFi blog io9 (I read it every day, and you should too if you like SF) has an article asking if Obama will destroy the space program. Not quite as nuanced as my own blog post on the subject, but then we both stole this from Popular Mechanics.

3) Also in PopMech, it looks like NASA has been rethinking dissing private space companies. The space agency has been giving prizes and awards to some companies; they just indicated they’re interested in using SpaceX for launches in the future. I’m glad to see this. I think private industry may be a lot more flexible when it comes to launched than NASA. I’ve been saying for years that NASA should spend taxpayer money to do things companies cannot do (pay for the design, building, and use of deep space missions; go to the Moon, develop new technologies and methods, etc.) and let private industry take over launches. NASA has proven quite effectively that they are not so great at getting cheap access to space. It’s not all their fault; being beholden to the White House and Congress would be enough to make any person insane.

4) I was asked on my live video chat last Sunday if any video of Pangea Day, and specifically Carolyn Porco’s talk, would be made available. The answer is, yes! It’s on YouTube now, at least the first 20 minutes of it. But it includes Carolyn… introduced by Queen Noor of Jordan! Wow. That starts about six minutes in, and it’s nine minutes of your life that will be very well spent.

5) My sister sent me a link to some incredible hi-res Shuttle images. Very cool.

6) Finally, Colbert interviews astronaut Garrett Reisman. It’s funny — huge duh — but you can tell Colbert is totally squeed by this.

7) Not space or science per se, but my bud Adam Savage was on Wait Wait Don’t Tell Me last week. Very funny!

… and you want proof he’s my bud? O foolish mortal.

Microsoft has finally released their long-awaited World Wide Telescope software today. It uses vast amounts of data from telescopes across and above the world, allowing you to pan and zoom across the cosmos much like Google Earth lets you view our own planet.

I’d love to post a review of it, tell you about its flaws and successes, but I have a Mac, and I don’t have Bootcamp. So for now I’ll go the safe route and assume it simply has huge software security issues, and running it will triple your spam, crash your computer, and give away your social security number to hackers.

If I have time later today I’ll download it on Mrs. BA’s PC and see how it goes. Stay Tuned.

The X-files movie trailer is up on YouTube, c/o Gia:

W00t! It looks great! Gia, who posted it, has a couple of screencaps, too. Gillian Anderson is still teh hawt, even maybe more so now. I loved that she was called "the thinking man’s sex symbol" back when the show was on. Even though the actress herself has a touch of the woo, Dana Scully was all science and a scorcher because of it. [Swooning sigh]. Obviously, Gia agrees.

I just spent the weekend at the Detroit Science Center in Michigan, where they premiered the Bad Astronomy planetarium show. Hmmm… sounds like a good idea for a book.

Haha. In fact, the show is based on my first book, and I’m in the show itself, hosting it and doing some of the narration (local radio personality Rachel Nevada also narrates). The show covers some popular misconceptions about astronomy like astrology, the Moon Hoax, UFOs, and others.

To be honest, I wasn’t sure how the show would turn out. I’ve heard rave reviews of other planetarium shows in the past, only to see them and discover they’re horrid. So it was with some trepidation I sat in the (very nice) planetarium at DSC while Todd Slisher (the VP of science shows) introduced the show. The lights went down, and it began… and it was pretty cool! I liked it! It’s got a good mix of serious and silly, with only a very light helping of cheese; too many shows really lay on the goofiness too thickly, but this one had a light touch that’s refreshing.

The audience seemed to like it too. Lots of them came up to us afterwards to tell us how much they liked it, which is an excellent sign. One man made a point to tell us that he learned a thing or two, and what better praise is there?

While I was there I also gave two talks at the DSC, and another at the nearby Cranbrook Institute of Science, and they all went pretty well. It always throws me a bit when a lot of little kids show up; my talks are geared more toward people older than about 10, but I made do… and I always get great questions from the kids (does the Universe go on forever? Are all the rocks on Earth meteorites?). It was a lot of fun.

If you’re in the Detroit area, then drop by the DSC and watch the show. And if you’re a planetarian yourself, consider buying a copy for the show for your own venue. I think it’ll be very popular, and that’s coming from a true skeptic who would never show any bias at all.