Archive for the ‘astronomy’ Category

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Does Saturn have a bee in its bonnet?

April 2, 2007

Cassini discloses Saturn's north poleThe solar system continues to be a prolific Wow! generator. Cassini, NASA’s spectacularly successful Saturn probe, has returned the first extensive pictures of Saturn’s north pole. And they are passing strange. The winds and cloud formations create a nearly perfect hexagon around the pole, a couple of earth diameters across.

Here’s a larger still picture, and here is the JPL press release .

The middle graphic on the right of the press release page shows a movie of the pole, with the hexagon rotating steadily counterclockwise. I don’t know about you, but that animation sends quite a chill up my spine. Lefty loosy, remember? What is preparing to emerge from beneath when that hexnut finally unscrews? The “face on Mars” was pretty spooky, but at least (1) it wasn’t real and (2) it didn’t bloody move.

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Some grand tours

January 19, 2007

As this Flash shows, Eric Idle’s song and NASA’s visual dance are a marriage made in the heavens.

And for those of you with high bandwidth, who are already weary of mere HDTV and bluetooth, here’s a page devoted to gigapixel photography. And here’s another.

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That’s funny, you look planetish

August 26, 2006

So Pluto’s planeteering days are over. As a card-carrying geezer, I guess I’m supposed to get all nostalgic and upset. But it was past time the astronomical community settled this thing, one way or another. And there was simply no intellectually honest way to maintain the old canonical nine.

I’ve seen quite a few horrified cries of “But think about the children!” The children were well served by this decision; better served than they would have been by the open-ended planet list of the committee’s Roundness Recommendation. Our solar system now has exactly eight planets, and always will.

Not that extrasolar planetary systems won’t trip us up down the road. Whether under the Committee’s scheme, or the one that got voted in, planets do not constitute a natural kind. Domination of an orbital region is hardly a bright line in the universe of possible arrangements of heavenly bodies. When we run into a former planet busted up into half a dozen pieces, or an asteroid-like belt with one major body and a couple of dozen lesser ones that failed to amalgamate, the sky solons will have to convene and scratch their heads all over again. But surely this definition will be serviceable for a generation or two. And that’s an eternity in science.

The one thing that “the children” now need is a standard classroom census of the solar system which isn’t planet-centric. The magic number is no longer nine, but it shouldn’t be eight either. It’s twelve: the eight planets, plus Sol, the asteroids, the Kuiper belt, and the Oort cloud.

May victimes evade Muhammad Ali’s jaw slamming uppercut? No: Knock Out!

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To boldly backtrack where none has backtracked before

July 23, 2006

The NASA mission statement as it was drawn up, with massive input from scientists around the country, in 2002:

To understand and protect our home planet.
To explore the Universe and search for life.
To inspire the next generation of explorers…
as only NASA can.

The NASA mission statement, as it was imposed last week from the top down:

To advance and communicate scientific knowledge and understanding of the earth, the solar system, and the universe.
To advance human exploration, use, and development of space.
To research, develop, verify, and transfer advanced aeronautics and space technologies.

The earth gets a one-word mention. We only want to “understand” it now, not to “protect” it. As befits the eternal Bush mantra: we are deeply concerned about global warming, which is why we want to study it very carefully for another few decades before we, you know, do anything about it. Not that there’s any real interest even in the “understanding” part. Last month, you may recall, the Bush administration deep sixed two previously approved programs to monitor moisture and climate.

This has, of course, nothing whatsoever to do with top NASA climatologist Jim Hansen’s frequent reference to the old mission statement as he has spoken out about the dangers of climate change.

Still more disturbing, I feel, is the demotion of Earth from its former status as “home planet.” How painful must be the pinch of exile felt by members of this Administration from their own home planet. But rather than terraform Mars, they are soldiering bravely on to bring our own blue-green globe under the rule of Mars, the god of war. Above, a photo snapped by our crack correspondent on location in the future, of downtown Washington D.C., once they’ve succeeded.

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Homing in on a home away from home.

May 31, 2006


Catching up on the implications of a two week old bit of science news. Nature reported that three new Neptune sized planets have been found circling the nearby star HD69830, 41 light years away.

This was gratifying news for three reasons. First, infrared studies had already disclosed the presence of an asteroid belt around the star. It was predicted that a pair of planets would be found, one on each side of the belt, acting as shepherds to keep the belts in place, much as the inner moons of Saturn shepherd the particles in its rings. So it was pleasant to see observation follow dynamical theory.

Second, detection of the planets was possible because of a big jump in the sensitivity of the Doppler technique for finding extrasolar planets, by observing the wobble they induce on the location of the parent star.

Third, at the new level of sensitivity, it still isn’t possible to find the holy grail of extrasolar planetary research: a rocky, earth-sized planet orbiting a sunlike star at a distance congenial to life. To do that, the sensitivity of the Doppler technique would have to be ratcheted up by another 90%.

But here’s the beauty part: most nearby stars are not sunlike. They are smaller: lighter in mass, and less bright. That makes a habitable planet easier to find on two counts. The habitable zone is closer in to the star, so that an earth-sized planet would tug harder at its sun. And the star is smaller, so that the same size tug would make it wobble further.

We’re getting close. The first planet around a different star worth a beamdown by Kirk’s crew should put in its appearance within the next three to five years.

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Titanic: the Movie

May 12, 2006

Here for your random edification and enjoyment is a time lapse movie of the Huygens spacecraft’s descent onto Titan. Also available is a more geeky version, with narration replaced by a soundtrack in which pitch conveys the angle of the parachute, and the patching together of the visual mosaic is not hidden from you.

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Black holes are green

April 28, 2006

The idea’s been around for a long time. Misner Thorne and Wheeler’s classic 1973 text Gravitation explained in Chapter 33 how to use a black hole to convert your garbage into electricity with astounding efficiency. They had a neato diagram of the ringworld civilization, the BH, and the trajectory of the garbage rocket.

A NASA press release Monday tells us we’ve proved it’s happening out there. The X-ray observatory Chandra was able to measure the efficiency of a black hole engine, which uses infalling gas as fuel to power a process that scoops out humongous cavities in the black hole’s surrounding material. (Here’s a larger photo.) Equivalent efficiency in a car engine would give you an EPA rating of a billion miles per gallon.