National Geo: Seeking new earths

rocket launch - from National Geographic

rocket launch - from National Geographic

There’s an article of interest in the December 2009 National Geographic, “Worlds Apart: Seeking new earths”. Written for National Geographic by stargazer Timothy Ferris, the article discusses, in lay editorial style, the mission of NASA spacecraft Kepler (the launch image on this page).

Also discussed with excellent graphics is a foldout showing new planets that have been found so far. The newsprint magazine also presents thumbnail concepts of current detection techniques, including subtle changes in parent star luminosity, and doppler wobble.

For those of us who don’t have access to the current old-fashioned subscription magazine (which I prefer), here are current links to the National Geo articles:

The chart covers the 373 found planets (as of when the issue went to press). I didn’t realize we had identified orbiting planets out to 10,000 light years distance. At least one “planet” is really a failed star (17 times Jupiter’s mass) – it should have gone thermonuclear.

Since Andromeda is our nearest neighboring galaxy, some 2.5 million light years distant, the article doesn’t report any discoveries there, and most likely none have been observed. For ET hunters it might be somewhat unsettling to realize that there is no way Earth could be seen from Andromeda with what we consider state of the art technology. Newly launched Kepler will peer out 15 times farther than current sightings, that is, 6,000 lights years distance, as opposed to the current 400.

In that case, where exactly are the host stars for our 373 observations to date? They seem to all be in own Orion Spur of the Milky Way’s  Sagittarius arm. Even Kepler is confining its search area to this spur.

For the seasoned amateur astronomer, there is perhaps not much content we haven’t read elsewhere, at some time or other,  in astronomy magazines and websites. But the National Geo presentation is well-organized, as generations have come to expect from that publication, and well worth our review.

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You Are Here, Part II

The graphic below follows up on yesterday’s article Debunking the “2012″ Myth. The question is: how exactly is a supposed alignment of the sun with the core of the Milky Way supposed to cause catastropic destruction in 2012?

Graphic map of Milky Way. For better detail, click image to link to source page at atlasoftheuniverse.com.

Graphic map of Milky Way. For better detail, click image to link to source page at atlasoftheuniverse.com.

In this graphic, our Sun is depicted as lying behind the Milky Way’s barred core, in the Orion Arm. Ask yourself:  how can I figure out when the Sun would be “aligned” with this bright central region?

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Summer Solstice

DSC_1844.jpg Potsam and Jetsam ... Click image for larger file.

This photo was taken June 20, 2006. I got around to posting it in Photos that August. It’s not that bad for a photo, and even though the light is interesting, it’s not the kind of photo I normally post to a gallery. I knew there was something special about it, but I couldn’t quite put my finger on it.

I should have asked Astronomy Mag’s Bob Berman, author of the Strange Universe column. Continue reading

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SETI

Project SETI Certificate - click image for larger view
Project SETI Certificate

I’ve been participating in Project SETI since 2003, when I joined the Cloudy Nights SETI team.

It’s not so much that I expect to be the first to detect signals from ET. In fact, as I’ve often joked, I’d rather that you detect them first, because then I get to stay at home and smoke my pipe, while you get to cope with the demands of the media.

What are the odds? We’ve only been listening for a few decades, hoping to detect coherent signals of any sort rising above the cosmic background noise. If we ever do detect a “signal”, the civilization that sent it might not even be around.  Listening searches might be confined to local areas of interest, such as the Orion Nebula (1500 light years). Mighty “sister galaxy” Andromeda, on the other hand, is some 2.5 million light years distant.
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How do gravity assists work?

A letter to the “Ask Astro” column, and answer, were published in the Dec 2007 Astronomy magazine.

How do gravity assists work?
ALEX FORBES, CASTRO VALLEY, CALIFORNIA

By passing near a large body, a spacecraft can radically alter its speed and trajectory without expending any fuel. This may sound like a free lunch, but it isn’t.
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Tar Baby Cosmology

I wrote a piece in another department about contemporary Zionism, observing that for me to suggest improvements would put me in the position of Bre’r Rabbit and de Tar Baby. You know, you think you hit ‘im, but he stick to you and you can’t get loose. And Brer Fox, he lay low.

Thinkers like Hawking and Feinmann, and their intellectual heirs and progeny at Cambridge, CalTech (and many other major university centers of theoretical research) provided us with a wealth of articles in respected layperson periodicals like Scientific American, Astronomy, or Sky and Telescope. Their intention no doubt was to bring to the public some of the distilled fruits of cutting edge science, and I am certainly grateful that a market for this kind of writing exists. You certainly won’t find in in People or USA Today.

Sometimes I wonder how much of this material they think the average reader absorbs.
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Getting to the Observable Universe

Roll up your sleeves. Some junior high school math with lots of powers of ten is coming up.

After all, honestly, it’s not as if I’d have the good sense to leave well enough alone. In the previous post, we discussed the current size of the “observable universe” (10 to the 28th power centimeters), and cosmology models that depend on “inflation” to explain how we got so big so fast. If, that is, you accept that the 14 billion year age of the universe is “so fast”.

But light travels pretty fast. If the universe only expanded at the speed of light, and (almost by definition, you’d think) has done so ever since the Big Bang 14 billion years ago, that would make a pretty big sphere today. Do we really need “inflation” to account for the 10^28 cm size of today’s “observable universe”?
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Fahrenheit 10^10^12

Periodically one might wonder why Herr Daniel Gabriel Fahrenheit fixed his temperature scale to a freezing point of water at 32 degrees, and the boiling point, at 212 degrees. Reading in Wikipedia that the numerical difference between boiling and freezing is exactly 180 furnishes one with relatively little additional comfort, unless one is planning a series of experiments in which the temperature of ice needs to be raised to boiling in exactly 180 annoying little increments.

For the big numbers of really hot stuff, of course, scientists use the Kelvin scale, so we say the surface of the sun has a temperature of about 8,500 Kelvin, whereas the surface of a white dwarf is closer to 85,000 Kelvin. For true convenience, this can be converted back to Fahrenheit using the formula TF = (TK whatever 459.67 … where we see that for big numbers the 459.67 conversion constant doesn’t mean a damn thing, and 85,000 x 9/5 is plenty close enough for government work.
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