Billion Star Surveyor 'Gaia' Lifts Off 77
mrspoonsi writes "BBC Reports: 'Europe has launched the Gaia satellite — one of the most ambitious space missions in history. The 740m-euro (£620m) observatory lifted off from the Sinnamary complex in French Guiana at 06:12 local time (09:12 GMT). Gaia is going to map the precise positions and distances to more than a billion stars. This should give us the first realistic picture of how our Milky Way galaxy is constructed. Gaia's remarkable sensitivity will lead also to the detection of many thousands of previously unseen objects, including new planets and asteroids. Gaia will use this ultra-stable and supersensitive optical equipment to pinpoint its sample of stars with extraordinary confidence. By repeatedly viewing its targets over five years, it should get to know the brightest stars' coordinates down to an error of just seven micro-arcseconds. "This angle is equivalent to the size of a euro coin on the Moon as seen from Earth," explained Prof Alvaro Gimenez, Esa's director of science.'"
Total map size (Score:5, Interesting)
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While this telescope is focused on high accuracy of closer stars, so it may not be finding any more galaxies, I wouldn't be surprised if it finds even more stars in the Milky Way than we previously estimated. This seems to happen every time we take a closer look.
From the article
it is likely also to see a colossal number of objects that have hitherto gone unrecorded - such as comets, asteroids, planets beyond our Solar System, cold dead stars, and even tepid stars that never quite fired into life.
It seems even the definition of star isn't always clear.
Re:Total map size (Score:4, Insightful)
Anyone who doubts this should go to YouTube and search for "Hubble Ultra Deep Field".
Amazing video...
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Given how long it will take to chew through Gaia data (Essentially, as someone starting out in astrophysics, this mission could define much of my working life) there won't be another powerful astrometry mission for a while.
Why are you fixated on having NASA try to one-up ESA though? NASA has its own top end science missions planned, doing other things. If you are lucky and take care of your space agency, so of them might actually fly in space.
Re: Hope Nasa can help us on that (Score:1)
Because "frontier." Americans have been conditioned since the dawn of the twentieth century to respond positively to the word "frontier" in rhetoric and funding proposals. It's part of the "Frontier theory" of history: basically, that America was exceptional and democratic because of its unsettled western edge, until it was finally settled, which made the exploration of "new frontiers" in technology and space the new site of American exceptionalism and freedom. It's the theory that consciously underpins th
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It would be silly to try to one-up ESA on this. It would be much better to fund these missions (and to hell with the pork-barrel manned missions):
Mars Sample Return
Europa Clipper, esp. in light of the plumes
Terrestrial Planet Finder
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Don't know how these two are related...
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The James Webb Space Telescope is the next big NASA space project although the funding has been on-off for the past decade, raising the final price and stretching the delivery time to 2018 and counting. It could still be cancelled by Congress to save money and help reduce the national debt. Europe is providing a number of instruments and an Ariane V launch for the project in return for access to the science.
The JWST is the last Big Space Science project on NASA's books though, all the other big observatorie
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You're talking about not wasting money but then in the next breath that the U.S. has to "win at space"? Last I checked, we weren't in a cold war with Europe or anything. Just call this a win. We don't need to one-up them. I know it's a radical concept, but maybe we could all SHARE information about space.
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It will find galaxies, sort of. Gaia doesn't really care what it is looking at, it simply tags every point of light in its field that is bright enough. Things that aren't stars are then to be discarded when the data is processed. There was a recent paper published suggesting that some of these discarded galaxies could be surveyed in order to get even more science value out of Gaia.
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Very little that Gaia observes is truly discarded -- just the main astrometric system needs a mix of stable, well behaved stars and very distant quasars, that could be between 10% and 50% of the objects detected. There will be an attempt to classify objects -- which you need to do in order to grab the quasars for the astrometric system
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Re:Total map size (Score:5, Informative)
500 Billion --A Universe of Galaxies: Some Older than Milky Way [dailygalaxy.com]
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Actually Gaia will map 1% of the stars, but a substantial (my guesstimate ~50%) volume of the region containing most of the stars, which will allow to map the principal structures of the Galaxy: its spiral arms and its stellar bar, as well as to constrain the distribution of dark matter. It is comparable to study one object, like the sun, to better understand all the stars; Gaia will map one galaxy well, ours, with the aim to better understand all spiral galaxies.
The size of a euro coin? (Score:3, Funny)
What is that in Metric? Wait, I mean American?
Re:The size of a euro coin? (Score:5, Funny)
What is that in Metric? Wait, I mean American?
Well, the diameter of a Euro is about 23.25 mm, giving it a surface area of about 425 mm squared. Given the ugly assumption that all 151,785,778 items in the library of congress are A4 sized (total SA ~ 9,466,878,973,860 mm squared), a Euro coin is about 4.5x10-11 of a Library of Congress.
I should probably do some work.
About the size of a quarter (Score:2)
Re:The size of a euro coin? (Score:5, Insightful)
Yes, the Europeans are going back to fundamental mapping of what is out there, like James Cook, Galileo, Johannes Kepler.
Onwards to L2 Gaia!!!
Re:The size of a euro coin? (Score:5, Funny)
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Well, at least today it is. I prefer my units of measurement to be in wavelengths of an excited atom or, at the very least, the distance between two scratches on a platinum bar.
(I think the point folks have been trying to make it that it would have been much more informative to say a ``N millimeter'' coin/object/whatever. Much of the world has probably never seen -- or ever will see -- a Euro coin except, maybe, in a photograph.)
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its diameter is .915 inch or 1.16 milli-furlongs :-)
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Are you sure you're European?
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Most Greeks/Europeans pretend to "hate" America. But even the Socialists/Communists -especially them!- (and we have plenty of them -in Greece and Europe-... unfortunatly) that are obligated by their ideology to hate USA -and everything and everyone else! - are the bigest supporters of the American economy... they just can't live without American stuff!
A bit like the American tea-party and Chinese products
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Re: The size of a euro coin? (Score:2)
Northern Europe is indeed more friendly towards the US than Southern or even Western Europe.
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Because Southern Europe tends to like capitalism less, which is what the US embodies.
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Paradoxically, the Republican voter base loves love Social Security. They just don't love social security.
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Now that doesn't mean a lot of Europeans are happy with the recent (last ~15 years) US government's politics re. their 'friends'.
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The Bush years were very trying on European patience, but there really isn't widespread animosity to Americans here. Please, don't let it stop you visiting. No, really, we are totally fucked here, bring your precious dollars ASAP. Help us!.
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the Western Civilization... the one we Greeks... created (!!!) That is a myth.
History likely had run pretty similar when Xerses had won over the greeks.
are the bigest supporters of the American economy... they just can't live without American stuff! ... ...
That is nonsense. The only american products I own is my Apple stuff
And I don't know anyone who owns anything made in america. Yes, ofc. you see the occasional american car on the streets and yes I guess many european air lines fly Boings
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In Metric, it is 23.25 mm.
In American, it is 0.95836768342951360263 times the diameter of a quarter. Or, in more standard units, 0.00021188757655293088 football fields. Approximately.
Re:The uncertainty is 775 miles at Alpha Centauri (Score:2)
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This being a European project you should be coloured impressed.
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Sure, I shouldn't kulør d'impressed seid?
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I was wondering how impressive it was and attempted to resolve this with trigonometry to find the likely error distance 1 light year away.
This got me in trouble with precision (the angle is of the order 1.0e-11 in Radians) but knowing that the angle is a constant here, the error should scale linearly with the distance.
If we use 400,000 km as the distance to the moon, 1 light years is roughly 2.0e7 times the distance to the moon (Google search calculator).
Thus an error of 20mm = 2.0e-5 km error at 400000 km
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Given how close the moon is,
Now I appreciate the US concept of distance is, especially for those from the mid-west, different to that of someone living in say Luxembourg or Belgium but to call the moon close is a bit of a stretch.
I mean, even with your low fuel prices such a 480,000 mi round trip might get expensive...
The real test... (Score:1)
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Well, Gaia won't ever observe the Moon, nor Venus and Mercury which are always on the sun-ward side of the solar-shield. Jupiter is so bright that it really messes with the detectors when it transits the focal plane, but it should be possible to do some interesting general-relativity experiments with the light-bending effects of Jupiter's mass for stars that are close (not not too close) to Jupiter when Gaia observes near it.
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In fact Gaia is sufficiently sensitive that General Relativity light deflection due to the sun and planets must be taken into account in all directions!
Excellent! (Score:5, Informative)
This is a mission I've been watching and waiting for for a while. The original Hipparcos mission did this sort of mapping for a much smaller volume of space.
Think of this as being like how finding the precise latitude and longitude of a large number of places on earth would have been to navigators of a much earlier era. No big new ideas, but it makes navigating so much easier and precise.
This does this for astronomy and cosmology in a greatly expanded region of space.
Something some don't realize is that our measurements of distance to stars and other objects in astronomy are very indirect. We use red shift to measure it in many cases, but that's an indirect method that relies on assumptions and estimates of the Hubble constant.
We also use what are called "standard candles". These are objects we know the brightness of from the physics of the processes going on. Certain kinds of supernovae are some of the best known. But, again, like measuring the distance to the next town by how bright the streetlights are, it's indirect and can have errors from intervening dust, for example..
This will use parallax, the same method as used in surveying to find distance from the change in angle between two separated observations of a far object. It's a direct method that relies on few assumptions.
Gaia I'm sure is honored. (Score:2)
Gaia is the first God, the God of all Gods and a women.
http://en.wikipedia.org/wiki/Gaia_(mythology) [wikipedia.org]