Gaia Probe Reveals Stellar DNA and Unexpected 'Starquakes' (theguardian.com) 29
Astronomers have unveiled the most detailed survey of the Milky Way, revealing thousands of "starquakes" and stellar DNA, and helping to identify the most habitable corners of our home galaxy. From a report: The observations from the European Space Agency's Gaia probe cover almost two billion stars -- about 1% of the total number in the galaxy -- and are allowing astronomers to reconstruct our home galaxy's structure and find out how it has evolved over billions of years. Previous surveys by Gaia, a robotic spacecraft launched in 2013, have pinpointed the motion of the stars in our home galaxy in exquisite detail. By rewinding these movements astronomers can model how our galaxy has morphed over time. The latest observations add details of chemical compositions, stellar temperatures, colours, masses and ages based on spectroscopy, where starlight is split into different wavelengths.
These measurements unexpectedly revealed thousands of starquakes, cataclysmic tsunami-like events on the surface of stars. "Starquakes teach us a lot about stars -- notably, their internal workings," said Conny Aerts of KU Leuven in Belgium, who is a member of the Gaia collaboration. "Gaia is opening a goldmine for asteroseismology of massive stars." Dr George Seabroke, senior research associate at Mullard space science laboratory at University College London, said: "If you can see these stars changing in brightness halfway across the Milky Way, if you were anywhere near them, it would be like the sun changing shape in front of your eyes." Gaia is fitted with a 1bn pixel camera -- the largest ever in space -- complete with more than 100 electronic detectors. The latest dataset represents the largest chemical map of the galaxy to date, cataloguing the composition of six million stars, ten times the number measured in previous ground-based catalogues.
These measurements unexpectedly revealed thousands of starquakes, cataclysmic tsunami-like events on the surface of stars. "Starquakes teach us a lot about stars -- notably, their internal workings," said Conny Aerts of KU Leuven in Belgium, who is a member of the Gaia collaboration. "Gaia is opening a goldmine for asteroseismology of massive stars." Dr George Seabroke, senior research associate at Mullard space science laboratory at University College London, said: "If you can see these stars changing in brightness halfway across the Milky Way, if you were anywhere near them, it would be like the sun changing shape in front of your eyes." Gaia is fitted with a 1bn pixel camera -- the largest ever in space -- complete with more than 100 electronic detectors. The latest dataset represents the largest chemical map of the galaxy to date, cataloguing the composition of six million stars, ten times the number measured in previous ground-based catalogues.
Stellar DNA my a** (Score:5, Insightful)
FFS, don't call it 'stellar DNA'. Pop science headlines are generally suckful deceitful clickbait, but this is an absurd analogy.
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You: Alex, I'd like Punctuation for $500
Alex: The answer, "Punctuation makes your prose understandable".
You: Uh..."what is a sentence but an interminable sequence of words conjoined together in the hopes of generating concepts?"
Alex: Close, but not correct.
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Re:Stellar DNA my a** (Score:4, Informative)
Pop science headlines are generally suckful deceitful clickbait, but this is an absurd analogy.
Yeah, terrible headline.
Some alternate sources:
https://phys.org/news/2022-06-... [phys.org]
https://scitechdaily.com/starq... [scitechdaily.com]
Not tsunami-like (Score:5, Insightful)
"Star-quakes" (more accurately, the excitation of one or more internal acoustic or gravity oscillation modes in a star) are neither tsnunami-like or cataclysmic, and TFA is pure clickbait. In most stars in which they've been detected, the brightness fluctuations they cause are well below the one-part-in-a-thousand level.
They do, however, have the potential to uncover the internal structure of stars, via the technique of asteroseismology. So, the Gaia DR3 release is pretty exciting stuff -- just no need to overhype it with Michael Bay adjectives.
Full disclosure: I am a computational asteroseismologist.
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"Full disclosure: I am a computational asteroseismologist."
I can barely even say that, I trust what you say!
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...So, the Gaia DR3 release is pretty exciting stuff -- just no need to overhype it with Michael Bay adjectives.
Full disclosure: I am a computational asteroseismologist.
(Michael Bay) Full disclosure: Technically I was hired to be the explosives adjective consultant. Not sure what they were expecting, but I thought it was pretty bad-ass...
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Full disclosure: I am a computational asteroseismologist.
Be careful with that shit! I'd hate for you to be the next David Carradine...
2003 is calling (Score:3)
This is really annoying, Guardian (which I like otherwise, ugh). Annoying because they say, "A star’s chemical composition is a bit like its DNA, giving us crucial information about its origin." so no it is not DNA. But actually finding amino acids with astronomy is a thing, it is exciting, and the headline had my hopes up to be dashed only by these stupid, ignorant, news hacks. Who not only just copy-paste huge portions of articles blythely and probably illegally, but also lack either scientific knowledge or a sense of contrition, preferring "bad-ass" stupid headlines when the Gaia probe is exciting to nerds without that foolishness. And if you do want to know about organic molecules in space, it is not the Gaia project as far as I know (tldr). Below link is from 2003.
https://physicsworld.com/a/ami... [physicsworld.com].
We can do better (Score:2)
Gaia has an impressive digital camera on it. Having said that, it's using camera tech that's over a decade old at this point and if you're going to build a segmented mirror, there's really no need to have the entire assembly launched in one rocket. You can assemble in space and adjust angles (as is being done with JWST) as needed.
IIRC, SpaceX launches are about a tenth the cost and launches are the most expensive part, so launching nine rockets to assemble a 3x3 set of modules (so triple the effective diame
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Gaia is incredibly useful despite the "old" tech. The magic of that mission is not in the size of the mirror: it is trying to measure stars in our own galaxy, not far away dim things across the observable universe. The magic is in the incredible precision of the astrometry it does: the mirror just has to be "good enough" to enable the rest of the instruments.
So many astronomical measurements are built on knowing the star's position and velocity. Gaia's whole mission is to measure those things with way
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The size of the dish determines two things - how sensitive it is to variations in a signal, and the angular resolution. A larger dish would measure position more precisely and measure change in signal more precisely. It also has fewer edge effects as a function of total signal, so you get higher quality information. So, yes, the magic of the mission is big time about the size of the mirror.
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Gaia is not taking pictures and doing things that are diffraction limited in the sense you're thinking of. If it were, its small mirrors would be limited to tenths of an arcsecond resolution. However, it is doing successful astrometric measurements down to handfuls of micro-arc seconds. How it does so is really cool: It spins and sprays light from two apertures at 90 degrees from each other, continuously clocks its CCD, and compares the signals as they walk across the CCD. The diffraction-limited point
Stellarium? Archaeo-astronomy? (Score:2)
With Gaia's 3D map of the nearest billion or so stars, when will Stellarium be able to accurately view the sky from any position in space? We have the data, after all.
If we've their relative velocity, we should also be able to calculate relative star positions within the last million years, allowing archaeo-astronomers the chance to test their ideas of what the sky would have looked like at different points in time. (Useful for testing the claim about the Pleiades myth, or for examining what the alignment w
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"any position in space"? For values of "any" within (very approximately) 3000 light years in the disc plane of the Milky Way and within a few hundred light years perpendicular to the disc.
A billion star positional database is on the order of 1% of the stars in the Milky Way.
Since people are regularly publishing on discoveries like "stellar streams" (material stripped from dwarf galaxies being "d
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6-12 Terabyte hard drives exist, I could see the entire data set being sold pre-installed on a single drive. Oh for the days of cartridge hard drives, when this was how data was supposed to be shipped and it was all pluggable!
Ok, a blu-ray cut-down version is much more likely, I can see that, and fair enough that you'd not want to manipulate that volume of data all the time, at least for home users. (For some reason, I want to limit that to home users not playing Elite: Dangerous. Wonder why I picked on tha
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I put one in my server a few months ago, when my 4TB drive reached 70% occupancy.
As part of the searching for prices on multi-TB drives, I discovered a corner of the (I think) BitCoin marketing ecosystem where they will sel you a drive populated with several TB of some sort of intermediate file in the processing scheme. Or maybe it's a cover for some other scam - it about doubled the apparent price of
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Oolite is fun, especially if you throw in the bars and some of the other expansion packs. The fact that it's expandable makes it a truly powerful game.
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I'd have to check the "Development" branch of the bulletin board, but since there's a "2" in the year number, I assume someone has come along this year and asked if there will ever be a multi-player version.
If in doubt, RTFriendlyP ... (Score:2)
AFAICT, this is article is a rehash of an ESA press release here [esa.int], which contains the (rather silly) "chemistry == DNA" simile and the various quotes used. It also has some videos and illustrations not used by the Grauniad article. In particular, down-thread I suggest to "jd" (with the 4-digit UID) that GAIA actua