Blogs / Bad Astronomy

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Man, I love the UFO proponents. You can always count on them for some great quotations.

So here’s the scoop. There are reports of a loud blast coming from the sky in San Diego, around 9:00 a.m. on April 4. They’re described as being like sonic booms, but there were no meteors reported, no explosions from a nearby marine base, no airplanes seen. What could have caused them?

On April 7, three days later, similar booms were heard in Mississippi. There are other reports from Alaska, Alabama, and other states, too.

Now, if I were faced with this situation, there are a lot of things I would suspect. There are air bases not too far from San Diego, for example, with some hotshot pilots. A low-flying plane might be missed, and it’s doubtful if it would be reported by the military. And Mississippi? There are several air bases in that area as well. Coincidence, maybe. The reporter does say the FAA said there were no transsonic planes in the area at that time.

Could it be a meteor? That’s possible. In broad daylight, a meteor coming in from the direction of the Sun might be hard to spot, even if it were pretty big. It depends on how big the area affected was. I tried mapping some of the locations listed in the article, but they were too vague to get a good line on. The article discusses it with an astronomer, who said a meteor is unlikely. I’d agree, but it’s not impossible. And it is pretty unlikely it’s been meteors causing all of these booms all over the place (unless crop circles know something we don’t).

But in a long list of things this might be, where do you think I would put UFOs?

If you said last, then yeah, that’s about right. Why resort to something for which there is zero evidence when there is plenty of evidence for more mundane things?

But for once, a UFO expert is in agreement! The article quotes Peter Davenport of the Seattle-based National UFO Reporting Center, who, when asked if these boom were caused by a UFO, replied, "Probably not."

Wow, I thought to myself when reading this. Logic, reason? Many people who believe in UFOs are relatively sane folks, but some of the more vocal proponents you hear from are, um, well, nutbags. I’ve heard Davenport on the occasional radio program, and he appears very earnest, and in many cases he does seem to be keeping a level head. I haven’t heard him very often, so I can’t make too much of a judgement.

The problem here is, in the article Davenport kept talking:

"UFOs almost never generate sonic booms or shock waves," he added. "They accelerate so rapidly that they leave a vacuum in the sky, much the way lightning does."

There are at least two silly things in his statement. One is the assumption that we know anything at all about UFOs, given the scant (read: zero) physical evidence for them. The best he can say is, with the anecdotal evidence we have gathered, alleged UFOs almost never make any noise. But ascribing a physical cause to that is asking for trouble…

… which is what he brought on himself. My favorite part of that quotation has to be his comparing them to lightning, saying this is why they are silent.

Lightning does create a vacuum in the sky, as he implies. It’s because lightning is very hot, and creates a sudden expansion of the air. This compresses the air violently, supersonically. This creates a shock wave. That makes… oh, what’s the word?

Oh yeah. Thunder. Lightning makes thunder! And that’s really kinda loud, don’t you think?

So hey, maybe a UFO did make these booms! Of course, you can be pedantic and say it was a UFO, because whatever it was, it was unidentified.

But pedantry is very tiring, and I would have to sigh and say you know what I mean.

Anyway, no, before you ask, I don’t know what’s causing these booms, but then I only read a newspaper article about them. I’d love to know what’s going on (especially if they are meteors) but I’m a bit busy these days. If there are any follow-up stories, BABloggers, please let me know. Link ‘em in the comments here. Maybe we can get some more clues.

Tip o’ the flying saucer beret to the approximately eight billion people who sent me email about this newsletter article. Also, the image up top links to a fantastic CGI site for Gerry Anderson TV show stuff. If you’re not familiar with his show, then what can I say? You’re too young.‘

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On April 24, 1990, Hubble Space Telescope was launched into space. I was in graduate school, having just finished my masters degree, and was looking for a PhD project. What timing! Hubble launched, and I hooked up with a team observing Supernova 1987A. After I got my degree, I continued to work with Hubble, calibrating and using the Space Telescope Imaging Spectrograph, or STIS.

After 16 years, and a few bumps in the road orbit, Hubble is still up there and observing the distant cosmos. The image above is of a weird galaxy called M82, which was once thought — understandably– to be exploding; the image was released to celebrate Hubble’s 16th anniversary in space. It’s now understood that M82 is undergoing a period of intense star formation, and the red junk you see in the image is gas and dust being expelled by the combined solar winds of millions of newborn stars.

Hubble has been an amazing observatory, and will continue to be for some time. There have been more space telescopes launched since Hubble, but it will always be remembered as the one that put astronomy into the consciousness of America and the world.’

Folks, my apologies. A massive deadline at work (grrr, do not get me started) has been eating up my life, both at work and away, so my blogging will be light for the next couple of days. I’ll write what I can, when I can.

In the last entry, I wrote about a new Trek movie in the works, and I was somewhat enthusiastic about it.

My enthusiasm has suddenly evaporated.

According to Trek Today (via Orac):

The as-yet untitled new film will be written by Abrams … Abrams is the creator of television series such as Felicity, Alias and Lost, and will soon be making his debut as a feature film director with Paramount’s Mission Impossible: III. He’s also written the scripts for films such as Regarding Henry and Armageddon.

Well, that’s that.

After the last two abominations from Yahoo!News, I am loathe to trust them, but this comes from Reuters, which means it’s probably true.

They are reporting that a new Star Trek movie is in the works. Can this really be? I figured Nemesis would be the last one, after it tanked in the theaters (it wasn’t very good, but it wasn’t truly awful). But who knows– even if it doesn’t do well, it’ll still make a ton of cash. They’re reporting that J. J. Abrams will direct it– he did Mission Impossible III, a movie you couldn’t pay me to see. Tom Cruise, as I have been known to say, is a freakin’ nutbag. But Abrams also did Lost which is kind of cool.

Still and all, I’d rather see Firefly back on the air, but this’ll do for now.

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In my last blog entry, I talked about how the Mercury probe MESSENGER took images of the Earth as it flew past our home planet a year after launch. In that entry, the focus was on the different filters the probe used.

But I only showed two images. In fact, MESSENGER took hundreds of images during that flyby, which means they can be strung together to get an animation. And that’s just what scientists did. The animation they made is phenomenal: it shows the Earth from a distance of just 66,000 kilometers– not much farther out than weather satellites orbit– and then continues as MESSENGER zipped past us, out to a distance of 436,000 kilometers — farther than the Moon — over the course of about 24 hours. Mind you, it took more than three days for the Apollo astronauts to get to the Moon, so MESSENGER is really hauling. During the movie, you can see the Earth rotating all the way around once.

So much for geocentrism.

Anyway, the movie is pretty big, more than 4 Mb, but it’s well worth the wait. The sense of being there on board the little spaceship is palpable. The images are really clear and clean, and there is something very special about seeing our blue marble against the velvet of deep space.

And oh, by the way: Dean was right. Ironically, this was sitting in my "post about it" pile for a long time, too.’

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The MESSENGER spacecraft is currently on its way to the innermost planet, Mercury. It launched in 2004, and will arrive at the tiny planet in 2011. Why so long? Mercury orbits the Sun very quickly, much faster than the Earth. Just getting there is hard enough, but if the spacecraft isn’t moving fast enough, Mercury will whiz right past it. So MESSENGER has to change it velocity by quite a bit (how much? Well, that’s a bit complicated ^* (hmmm, I’m having trouble getting the anchor linking to work. Scroll down to see the footnote)). There isn’t enough fuel on board to do it, so they borrow the velocities of Earth, Venus, and even Mercury itself to get the spacecraft moving rapidly enough to catch up to the mercurial (hahaha! ha!) planet.

When MESSENGER flew by the Earth in August of 2005, the engineers back home decided to test the cameras. They got the images above (click for a higher-res version). They’re lovely! The one on the left is a "true color" image, adding red, green, and blue filtered images. You can see South America there in the center. On the right is pretty much the same view, but instead of red light, they used blue-green-infrared. Vegetation reflects IR light very well, and so the Brazilian rainforest acts almost like a mirror in IR. It shows up as very red in this image. MESSENGER detected life on Earth from more than 100,000 kilometers away!

Well, not really. Lots of things reflect IR, but it’s still pretty cool. The cameras on board are pretty hi-res, so when it gets to Mercury the images will be spectacular.

Still, for nifty images we don’t have to wait that long (as the images above show). Later on I’ll post another cool thing MESSENGER did on that flyby of Earth…

^* One problem is that Mercury’s orbit is elliptical, and so it changes its velocity around the Sun. At the nearest point in its orbit (perihelion) it moves about 60 kilometers/second. At the farthest point (aphelion) it’s only moving about 40 km/sec. For reference, the Earth moves about 30 km/sec. So how much velocity the spacecraft needs depends on when it gets to Mercury. It looks to me that orbital insertion occurs at Mercury perihelion, which strikes me as odd, since that means they need to add more velocity to the spacecraft for it to enter orbit. There must be some logical reason for it, of course. Emily, if you’re reading this… ‘