Archive for the 'Astronomy' Category

Aug 27 2010

Weird Science

Published by under Astronomy,Physics

I love it when researchers turn up new data or new theories to explain old data that expose some interesting new gap in what we think we know about the universe. It’s from those interesting new gaps — like absorption lines in what should be a smooth spectrum — that lead to new science and new technologies. (Those absorption lines, in 19th century observations of the Sun, ultimately led to quantum theory — and modern electronics and lasers.) This week we’ve had several instances of this.

You’re probably aware that the universe is expanding, and even that it seems to be expanding at an increasing rate. This somewhat counter-intuitive observation has been explained by “dark energy”, some unknown force that is accelerating the expansion. But many scientists aren’t comfortable with dark energy; the numbers for the vacuum energy don’t work out, and it seems to violate conservation laws. Now, this presumed expansion acceleration is based on measurements of very distant (edge of the universe distant) supernovas. If there’s another explanation for those measurements, then the acceleration may not really be happening and thus we don’t need dark energy to explain it.

There’s another problem. Models of the Big Bang that started the universe predict the creation of a certain amount of hydrogen, deuterium (heavy hydrogen), helium, and lithium. Our observations of the first three match pretty closely the predictions — but we only see about one-third the lithium we think we should.

Cosmologists Marco Regis and Chris Clarkson think they have an explanation for both of these discrepancies. Scientists make the assumption that the universe is pretty much the same in every direction we look, that — celestial bodies aside — there’s nothing special about one part space over any other. Regis and Clarkson point out here that the above problems go away if don’t assume the universe is homogenous. But there’s one other thing: if that’s the case, and there’s a huge bubble of space that is lithium-deficient, then why is Earth in the center of it?

Speaking on inhomogeneities in the universe, two different deep sky studies by the Keck telescope in Hawaii and the Very Large Telescope in Chile have turned up unexpected differences in what’s called the fine structure constant, considered to be one of the fundamental constants of nature (it relates to how strongly atoms bind their electrons). The really interesting thing is that while the Keck observations suggest that the fine structure “constant” was once smaller, the VLT observations suggest that it was once bigger. (Papers here and here.) These two telescopes — one in the northern hemisphere, one in the southern — look at two different regions of the sky. This, especially in light of Regis and Clarkson’s conjecture, raises all sorts of interesting questions. (Such as: What affect does this have on chemistry — and biology — in different regions of the universe? Would a space ship travelling such distances drag its own fine structure constant with it, or would it change according to local conditions? And, what causes this “constant” to vary, and could we reproduce that effect locally? Larry Niven had disintegrator guns that worked by “suppressing the charge on the electron”; could that really be possible? If you could reduce the charge on a proton, wouldn’t that make fusion easier?)

Somebody (Asimov?) once said that real scientific discoveries are less often heralded by “eureka!” than by “hmm, that’s odd.” Looks like we have several “that’s odd” moments going on. Cool!

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May 15 2009

Astronomy updates

Published by under Astronomy

It has been another good week for astronomy, in particular for space-based astronomy.

The Hubble Space Telescope repair mission has been the biggest of such news items, and at the moment seems to be going well. This week (yesterday, in fact) saw the successful Ariane launch of two European space observatories, the Planck observatory to investigate irregularities in the cosmic microwave background, and the Herschel telescope, which is essentially a souped-up Hubble (it’s mirror is 1.5 times bigger than Hubble’s). All will add significantly to our knowledge of the universe as a whole and the various planets and stars in it.

But it gets better. This week another space-based telescope, NASA’s Kepler spacecraft, began its formal mission to, as Star Trek puts it, seek out new worlds. It is specifically intended to look for Earth-like (terraform, if not terraformed) planets around other stars. Over the next three-and-a-half years it will examine over 100,000 stars. The observatory itself was launched in March and its telescope saw “first light” in April. Between then and now it has been going through testing and calibration. This past Tuesday (5/12/09) it was pronounced ready for its primary mission. Kepler is designed to look for planets as small as Earth orbiting their stars in the habitable zone (where temperatures could let surface water remain liquid on at least part of the planet). I’m eagerly awaiting results, the first of which will be transmitted from the satellite in mid-June.

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May 07 2009

Tau Ceti

Published by under Astronomy,T-Space

This past week-plus has been pretty hectic. Jill came back from Ohio with a truckload of her parents’ possessions, which we’re still finding homes for (including storage), and we have to get the place prepped for when her mom comes up later this summer.

I did get another T-Space page written, this one about Tau Ceti, a nearby Sun-like star that has been both a popular location in SF and a prime target for SETI (Search for ExtraTerrestrial Intelligence). It occurs to me that I haven’t really written much set in that locale; I’ll be changing that shortly.

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Apr 24 2009

Gliese 581

Published by under Astronomy,T-Space

It was another good week for planetary astronomy, with the announcement of the discovery of the smallest exoplanet (planet orbiting another star) yet, only twice Earth’s mass, orbiting the red dwarf Gliese 581. The planet, dubbed Gliese 581 e, orbits very closely, and would be too hot for life as we know it. However, in other news from the same system, one of the earlier discovered planets (we now know of four) Gliese 581 c, is orbiting in the habitable zone, which means liquid water could exist. It’s a big planet, Neptune-size, and may very well be a water world. Of course any moons it has (which would be too small for us to detect yet, even if they were large by our standards) would also be in the habitable zone.
Gliese 581 and planets
Currently exoplanets are named after their parent star with a lowercase letter in the order found, with “a” reserved for the star itself. Thus Gliese 581 c was the second planet discovered orbiting that star, the recent Gliese 581 e the fourth. This has nothing to do with the traditional (at least in sci-fi) convention of using roman numerals to indicate position from the star; until we discover all the planets a star has, we won’t know the order. But at the moment, until we discover more, Gliese 581 e would be Gliese 581 I, and Gliese 581 c would be Gliese 581 III.

Gliese 581 is only about 20 lightyears from here, within T-Space. I really need to set a story there.

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Apr 13 2009

Updates – Footprints and T-Space

Published by under Astronomy,T-Space,Writing

I just received the proofs for the anthology Fooprints, where my story “Snowball” will be appearing. It looks great! I’ve only skimmed it so far, but there a lot of wonderful stories in there. I’d buy it even if my story wasn’t in it. (grin).

As promised earlier, I’ve added a page on Alpha Centauri to the “T-Space Encylopaedia”.

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Apr 08 2009

More T-Space

Published by under Astronomy,T-Space,Writing

I’ve added a page on the star system Delta Pavonis to the T-space pages. I plan to add pages there on a regular basis. They give the astronomical facts about the star (or other location) and some detail about how it fits into my T-space stories, and other writer’s stories too, occasionally. As best I can I want to keep things consistent with what we know about other star systems, but that still leaves plenty of room to play in what “hasn’t been disproved yet.”

Next up will probably be Alpha Centauri, a popular location for countless stories (being our nearest neighbor, and all). It’s possible, astrophysically, for both the main components (Alpha Centauri A and B) to have habitable planetary systems. I’ve also just found out something odd about it that has serious implications for T-space: its galactic orbit is very different from ours.

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