Archive for the ‘Impacts’ Category


More vacation astronomy: Meteor Crater and Lowell Observatory

May 29, 2012

Last week was full of cool astronomy-related stuff after the eclipse. Monday night I stayed up until after midnight to watch the launch of the Falcon 9, which successfully delivered a Dragon capsule to the International Space Station. Then on Wednesday London and I went to Meteor Crater and Lowell Observatory. The closer, brighter range of hills on the right in the above photo is the rim of Meteor Crater, which rises 150 feet above the surrounding plains.

In the courtyard of the visitor’s center is this boilerplate capsule from the Apollo program. Boilerplate capsules were used for all kinds of testing: parachutes, launch escape systems, touchdowns on land and water, you name it. This is the second one that London and I have seen in the wild–there is also one at the Columbia Memorial Space Center in Downey, California (darn it, I’ve been meaning to blog about that place for about a year now). This isn’t just a random space decoration, either. The Apollo astronauts trained at Meteor Crater with mock suits and backpacks before being launched to the moon.

Here’s the crater itself. It’s too big to fit into a single photo, unless you’re in an aircraft or have some kind of fish-eye lens. The crater is a little over three-quarters of a mile across, and a little under 600 feet deep, not counting the raised rim.

It is extremely windy, too.

Here’s the view to the southwest from the highest observation platform–the platform shown in the previous photo is in the lower middle of this image.

The wind up there was shockingly strong. I’ve been in 60-70 mph winds in desert storms and I think the gusts up there on the rim were about that fast. I’m a big dude, and not used to being pushed around by air, but the wind quite literally sent me stumbling a couple of times. Fortunately there were handholds all over the place.

I set my camera to maximum zoom to get this shot of the fenced area in the center of the crater. If you click through to the full-res version, you may be able to make out an American flag and life-size astronaut standee at the near right corner of the fence. People walking around down there would look like ants.

There was a nice museum inside, which we had to rush through because we spent all our time outside gawking at the crater. I did stop to get pictures of these shattercones, which only form under impact craters and nuclear explosion sites. Shattercones have a nice fractal structure, and range in size from microscopic to tens of meters tall.

That evening we drove up Mars Hill in Flagstaff to visit the Lowell Observatory. This segue photo shows a chunk of the Meteor Crater bolide on display in the observatory.

Flagstaff is a cool place for many reasons, not least the enlightened attitude toward light pollution–or rather, against light pollution. The city is plenty well-lit and never felt dim from ground level at night, but that’s because the residents use their power intelligently, with fully shielded, modestly bright light sources that face the ground. From the overlook on Mars Hill, based on the nighttime lights, you’d think it was a town of six to ten thousand. The actual population is just over 60,000. From the parking lot of our hotel I could see hundreds of stars. I have never seen such dark skies from inside any town of more than a thousand people. And they’ve been doing this in Flagstaff since 1958–when is the rest of the world going to wise up?

Of course, a big part of the reason we went to the observatory was to see the big 24-inch Clark refractor, which has been gathering starlight there since 1896. It looks like a near-perfect miniature of the 36-inch Great Lick Refractor, which also has Clark optics and went into service just 8 years earlier. Percival Lowell used this telescope to chart what he thought were canals on Mars. Lowell’s writings about the ingenious Martians carrying water from the polar ice caps to water their dying world inspired both H.G. Wells and Edgar Rice Burroughs. Both of the latter authors played a big role in shaping my young mind, and I still revisit them periodically, so it was fitting that I finally visit the telescope that made it all possible (even if the canals turned out to be illusory). In a sense, Barsoom was born in this dome.

Speaking of the dome, you’ll notice that it is made of wood and rotates on automobile tires. Those were obviously not part of the original design, but they’ve been in place for decades now. According to Timothy Ferris, who included a charming chapter about this observatory and this telescope in Seeing in the Dark, when one of the tires goes flat, the observatory staff jack up the dome to fix it.

The “smart end” of the telescope looks like some steampunk enthusiast’s fantasy incarnate. It could pass for the control column of the Nautilus. The effect is only slightly diminished by the Telrad perched opportunistically amidst the Victorian gizmos.

I realize that I haven’t said anything about Pluto. It was discovered at Lowell Observatory, but not with this telescope. I’d say more about it but I have nothing to say; I went up Mars Hill for Mars, not Pluto.

This was London’s favorite exhibit: a beach-ball-sized model of the sun filled with little plastic balls representing the Earth, to scale. It’s a fitting cap to this post, because it points the way toward the transit of Venus next week, when those blessed by geography and weather will see an Earth-sized speck moving across the face of the sun (about three times bigger than the Earth-spheres appear in relation to the sun-sphere in this display, since our sister planet’s orbit around the sun is two-thirds the diameter of our own). I may not have time to post again before then, so: clear skies!


The unrestrained Jupiter worship has got to stop

September 3, 2010

In a comment on the recent Jupiter impact post, Mike asked,

Uh. If this [i.e., big things slamming into Jupiter] is happening to Jupiter three times in thirteen months, what does that tell us about the odds of it happening to us?

The answer is that Jupiter giveth, and Jupiter taketh away.

In my experience, about 99% of the popular sources out there only mention the second, positive part: Jupiter is the solar system’s vacuum cleaner, hoovering up tons of wayward comets and other “small bodies” (all the way down to mere dinosaur killers) that would otherwise bomb us back into the Paleocene. The spate of recent impacts would tend to confirm that. Three cheers for Jupiter! Our hero! Let’s have a ticker tape parade!


Can we all take the Jupiter worship down a couple thousand percent? Because that ain’t the whole simple story. Jupiter also giveth, and what it giveth, we don’t wanteth.

Ever wonder why there are so many Earth-crossing asteroids?  I mean, the solar system has been here for close to 5 billion years. Shouldn’t the space rocks have hit something or gotten shot out of the system by now? In fact, the vast majority of them have. Earth-crossing asteroids have orbits that are stable on multi-million year timescales… which means that on the multi-billion year timescale of the solar system, they should be history. But they’re not, because new ones keep migrating in from the asteroid belt all the time, to replenish the ones that either get flung elsewhere or (gulp) hit us. And why do new asteroids keep coming in from the belt? Because of orbital resonances with stinkin’ Jupiter. That big bully keeps throwing rocks at us!

Now, it’s true that most near-Earth asteroids are destined to either spiral on it toward the Sun or get flung out of the inner solar system, and that only a very small fraction actually hit the Earth. And it’s also true that Jupiter sucks up a lot of comets and asteroids that might otherwise come in and hit us, and that the occasional impact damage from Earth-crossing asteroids is probably preferable to getting creamed by an unfettered rain of comets barreling in from the outer solar system. So on the balance, we’re better off with Jupiter than without. Jupiter is like that one tough guy among your childhood friends, who would keep other groups of kids from hassling your group, but might punch you really hard in the shoulder once a while, for no apparent reason.

So let’s lay off with the fawning science news coverage and virgin sacrifices. Jupiter is nice to have around, but it is nowhere near 100% cool.


In other news, I took the shot at the top from my driveway the other night, shooting with a Nikon Coolpix 4500 through an Orion XT12i telescope and 13mm Stratus eyepiece. The moons from left to right are Ganymede, Io, and Europa. I could see Callisto off to the right as well, but it was out of this shot.


Sigh…another impact on Jupiter

August 23, 2010

Well, it’s happened again. Something hit Jupiter while Earthlings were watching. Why is this newsworthy? It’s only the fourth time it’s happened in recorded history, but the third time it’s happened in the last 13 months. It seems increasingly likely that Jupiter is getting creamed by rocks that would dwarf the dinosaur-killer (seriously, the fireballs we’ve been seeing on Jupiter are the size of continents) all the time, but we’re just now catching on because finally enough amateur astronomers are watching (and digitally recording) the planet to provide something approaching continuous monitoring.

That’s right: amateur astronomers. All three of the recent impacts were found by amateurs. This latest was independently detected by two Japanese amateurs, one using a 6″ scope and one a 9.25″ scope.

More info and a link to a video of the impact at both Sky & Tel and Space Weather.


Commence strategic bombing of the moon!

October 6, 2009

moon impact

Friday morning at 4:30 AM Pacific time, NASA is going to slam the Centaur upper stage of a big rocket into the moon at something like four miles per second. At that speed, I could get back to where I grew up, in Oklahoma, in less than four minutes. The reason NASA is bombing the moon is to see if there might be water ice in one of the permanently shadowed craters at the lunar south pole–potential prime real estate for future manned missions. Following a bit behind the rocket stage is the LCROSS (Lunar CRater Observation and Sensing Satellite) probe, which will search for signs of water as it flies through the debris plume. LCROSS is also going to send us pretty pictures before it slams into the moon just four minutes later.

Big telescopes across the planet will be watching, and lots of little ones as well. The debris plume is expected to be about 6 miles tall, which means it should be visible in telescopes 10-12 inches in diameter or larger. I don’t have a scope that big, but I have a friend with a 16-inch Dob and I’m off work Friday, so we’re going to put in a full night of observing and cap it with an impact watch.

It’s worth pointing out that the Centaur is going to hit the moon with considerably more kinetic energy than anything manmade has before. Nobody really knows for sure how this is going to shake out–not just the water part, but the debris plume itself. There may be folks with 12-inch (or even 16 inch!) scopes who see nothing, or on the flip side it might be visible to smaller instruments (you know, the kind I’m usually yakking about). So it’s probably worth getting up for if it will be visible from your location (sorry, Europe and Eastern seaboard). If not, NASA TV will have live and streaming coverage.

NASA has a pretty great page about the mission here, with loads of info that you’ll probably find useful whether you plan to observe the impact from your backyard or your sofa.

Take that, Luna!