Blogs / Bad Astronomy

I’ve posted quite a few pictures from NASA’s Earth-observing Terra satellite over the past few months, some of them showing devastating natural disasters. But I never thought I’d post one that shows something so close to home.

This image was taken yesterday, September 6th, at about noon Mountain time:

That shows the plume of smoke from the Fourmile Canyon fire that I wrote about yesterday. The image is roughly 300 km (190 miles) across. The vertical dividing line is the actual edge of the Rocky Mountains; to the left (west) are the mountains, and to the right (east) is the start of the Great Plains stretching most of the way across the US.

The green smudge just to the south of the plume is Denver, and the smoke goes directly over Boulder… and my house. The fire is still going as I write this, but the winds have shifted and there is no longer a plume overhead. It smells like ash outside though, and the foothills — usually visible a few kilometers to the west from my house — are almost totally hidden.

I appreciate all the notes and tweets I’ve gotten, but we’re safe here. The fire is pretty far west of us, though we could see it poking over the first set of foothills last night. Creepy.

My brother-in-law has taken some amazing pictures of the fire from his house, located even farther to the east than where I am. This one shows the tops of the fires.

I’ll add that the sunset yesterday was desperately beautiful:

The smoke is made up of tiny particles of soot and ash. When blue light hits them, it scatters like a pinball off a bumper. So when you look to the Sun through the smoke, all the blue light has bounced off in a different direction, leaving only the redder light able to make its way straight to your eye. This happens on a lesser scale every night with particles in the air, making sunsets red. But this fire has really strengthened the effect, and the Sun went through myriad shades of red on its way down past the mountains last night. It was astonishing. Making it even more wrenching was knowing what was a causing it, and that there were people in the middle of all that smoke trying to put the fires out.

So far, there are still no reported injuries, though many homes have been destroyed and over 1000 people have been evacuated from the area.

My thanks to NASA_GoddardPix for the link to the Terra picture.

Some astronomical pictures are simply and truly cool.

And this, my friends, is near the top of the list.

[Click to enlasenate.]

Yes, the wow factor is high with this one! And the thing is, what you see is what you get: it’s a laser shooting out of an observatory straight up into the heart of our galaxy!

The observatory is of the European Southern flavor, in Chile. It houses the Very Large Telescope, which has a very nice little tool it can use: a laser guide star. The laser shoots up into the sky and excites atoms in the upper atmosphere, causing them to glow. That makes an artificial and very bright star in the sky! The telescope can then use that star to track the distortions in the atmosphere and compensate for them, allowing the images it makes to be incredibly clear and sharp.

Although it doesn’t say so explicitly in the press release, given where the laser is pointing I’m guessing they were observing stars orbiting the supermassive black hole in the center of the Milky Way. Read the rest of this entry »

[Update 20:20 MDT: My brother-in-law took some amazing pictures of the fire, including this one of the reddened sunset, and this one after dark.]

Right now as I write this there is a pretty big wildfire in Gold Hill, Colorado, about 15 kilometers west of where I live. There’s a thick pall of orange-brown smoke going straight over us.

This is the view to the west a little while ago, toward the foothills of the Rocky Mountains:

You can see the Flatirons to the left. The smoke totally blocks the hills north of there though. The smoke is much wider now from my view, covering almost 90° of the horizon, and the plume is clearly several kilometers across.

The Sun is shining through, but it’s dulled to an orange ember:

Ironically, the morning started off cool and breezy, the first autumn-like day we’ve had. I went upstairs to tell The Little Astronomer to open her windows to let in fresh air… and when I opened her shade I saw the plume.

[Update: I just walked outside (12:30 MDT) and there's ash falling all around us. It's very light, but holy crap.]

We’re safe here, I’m sure, but we can certainly smell the smoke, and the sky has an eerie cast to it. It’s been dry this year and the fire danger is pretty high. I hope they can contain this quickly, and that everyone involved is safe.

I sometimes think I’ve seen everything there is in the sky, with nothing new left to see.

Then I get a rude — but welcome — wake-up call.

Check.
This.
Out.

[Click to enspiralnate.]

When I first saw this picture, my reactions, in order, were:

1) What the frak is that?

followed immediately by

2) This must be a fake!

But it’s not fake. It’s real, and it’s the dying gasp of a very, very strange star system.

The name of this thing is AFGL 3068. It’s been known as a bright infrared source for some time, but images just showed it as a dot. This Hubble image using the Advanced Camera for Surveys reveals an intricate, delicate and exceedingly faint spiral pattern. It’s so faint no one has ever detected it before!

So what’s going on here? First off, this is not a spiral galaxy! Read the rest of this entry »

In the late 1970s, NASA landed two probes on the Martian surface. The Viking missions were designed to scoop up surface material and examine it for indications of life.

What was expected was for the missions to detect organic compounds: carbon-based molecules like amino acids that make up the building blocks of life. Instead, the results they got were disappointing. Instead of organics, they found compounds of chlorine like chloromethane and dichloromethane, which were interpreted as contamination from labs back on Earth (from cleaning fluids!).

However, in 2008, the Mars Phoenix lander did its own scooping, and found something unexpected: perchlorate. This molecule is made up of one chlorine atom and four oxygen atoms (ClO₄) and has the interesting property of being very reactive with organic molecules. It’s found naturally on Earth, too.

What’s so very interesting about this is that recently, scientists took samples of soil in Chile, added perchlorate, and then analyzed those samples in the same way Viking did. Guess what they got?
Read the rest of this entry »

[Update: the video has been removed the by the owner. I'm not sure why, so I dropped him an email about it. Stay tuned!]

This is pretty cool: back in July 2007, an amateur astronomer made a video of the International Space Station as it passed directly in front of the Sun:

Cool!

There’s a lot to note here:

1) Most obvious is the speed of the ISS. It orbits the Earth a mere 350 or so kilometers (220 miles) up; I like to say that if you live in DC and see it pass overhead, it’s about the same distance from you as New York City. So it’s actually pretty close to the Earth’s surface, and screaming around at 8 km/sec (5 miles/sec). That’s a good clip! From the point of view of someone watching from the ground, it only takes a couple of minutes for the station to go clear across the sky, horizon to horizon.

Also, the Sun is pretty small in the sky; you can easily cover it with your outstretched thumb. So the great speed of the ISS coupled with the small apparent size of the Sun means the entire pass will take less than a second!
Read the rest of this entry »

When all is said and done, the outer solar system must be a pretty scary place to live. How’d you like to live in a location that has a battle-scarred history like this?

That’s Saturn’s moon Dione as seen in by the space probe Cassini in a recent pass of the small world. Earlier today (September 4, 2010), Cassini dipped to a height of less than 40,000 km (25,000 miles) above Dione’s surface — that’s about the same height as weather satellites above the surface of the Earth!

The landscape of Dione is shockingly battered. Craters are everywhere, indicating a fierce history of meteoric bombardment. It is also heavily littered with cliffs and chasms.

I learned something incredibly interesting looking up information about the moon: Read the rest of this entry »