We Are Here, And So Is Everything Else

Courtesy of the ESA

The Gaia satellite, operated by the European Space Agency, is a fascinating project. Equipped with a billion pixel camera, it's goal is to produce the largest, most accurate 3D model of the Milky Way we've ever been capable of. It does this by charting the positions and velocities of every star in it's field of vision with razor precision and accuracy, and in real time (real time being a relativistic phrase here, as the light from the stars it is tracking would be anywhere from years to multi-millenia old). This will allow scientists to better make calculations about it's stellar evolution and make predictions on it's future.

Some sides effects of it carrying out it's mission are images like this one above. This image is a density representation of looking straight down the barrel of the Milky Way. Because we are far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy, and pretty much dead centre in the 1000 light year depth of the plain, when we look into our home, we can only see it as a ribbon, rather than the full spiral we know it to be. Until Gaia finishes it's project, the best we can assume is that it looks reasonably like our neighbour Andromeda.

But this image is a beaut. The bright spots represent the highest density areas, and the dark areas the lowest. Or, where star density is obscured by deep dust and cloud regions. And because the image is generated in a purely binary colour scheme, the effect is unusually true-to-life. Images released by NASA from equipment like Hubble are often composite images, combining visible light, infrared, x-rays and other degrees of the spectrum to create vibrant and clutching images. This image contains no such composites, and therefore more closely resembles what the human eye would see if taking this view in itself.

One last interesting note: it may look as though this image has been taken at some distance, as though some lone camera floating in the void between galaxies turned toward home and took one last photo before reseeding into the darkness, instead of being assemble in the thick of things. The answer is, the light from nearby objects was actually too bright to be used as viable data (a nearby star would have the same luminosity of an entire dense cluster on the far side of the galaxy) so neighbouring objects have been disregarded. Andromeda is absent, but the further and dimmer Magellanic Cloud galaxies can be seen just under the Milky Way plain. The end result is a beautifully disconnected image, that shows our home at arm's length, which is a perspective we are rarely afforded.

Via Phys Org.