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Comment by dylan604

4 days ago

I get how Gaia could make the best edge on image, but how could Gaia (or anything man made) get the the "best" face on image?

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dylan604

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goodcanadian  3 days ago

The whole purpose of Gaia is to precisely measure the position of stars (and other objects). Once positions are known, a 3D model can be built. But how are the distances measured? The answer is parallax, essentially triangulation. You look for very small changes of position against the background sky. You use the width of the earth's orbit as the baseline and measure at different times of the year.

iAmAPencilYo  4 days ago

All of these are "Artist's Impressions". My best guess is they run a simulation based on the data from the spacecraft and then can pan the camera around as they see fit

  • BizarroLand  4 days ago

    From the page:

    [Image Description: A model image of what our home galaxy, the Milky Way, might look like edge-on, against a pitch-black backdrop. The Milky Way’s disc appears in the centre of the image, as a thin, dark-brown line spanning from left to right, with the hint of a wave in it. The line appears to be etched into a thin glowing layer of silver sand, that makes it look as if it was drawn with a coloured pencil on coarse paper. The bulge of the galaxy sits like a glowing, see-through pearl in the shape of a sphere in the centre of this brown line.]

    • hahajk  3 days ago

      That's an AI produced accessibility description so I thought it seemed wrong. But more directly from the article text: This is a new artist’s impression of our galaxy, the Milky Way, based on data from ESA’s Gaia space telescope.

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  • dylan604  3 days ago

    "The best Milky Way map, by Gaia (edge-on)"

    The "by Gaia" implies the opposite to me. Unless the "artist's impressions" are from someone named Gaia???

    • Cthulhu_  3 days ago

      "This is a new artist’s impression of our galaxy, the Milky Way, based on data from ESA’s Gaia space telescope."

      I'm sure you know of headlines vs details; when it comes down to it, space science relies on marketing to get some funding and interest in it, and using 100% accurate headlines is not good marketing.

sbierwagen  3 days ago

It can't. The galaxy is assumed to be roughly symmetrical, and they fill in the missing data with what we can see on our side of the galaxy. It's "best" in the sense that it's the most accurate fiction, I suppose.

Gaia is good to about 13,000 light years: https://en.wikipedia.org/wiki/File:Galaxymap.com,_map_12000_...

The Milky Way is maybe 100,000 light years in diameter. So we're only getting good distance readings on a small fraction, and nothing behind the central bulge of our galaxy. The first won't improve until we send an astrometry telescope way outside the orbit of the Earth, for better baselines, and the second is going to need a telescope sent 10,000 light years out of the galactic ecliptic.