BellaOnline
Posted By: Mona - Astronomy Gaia - 04/25/18 11:00 AM
What is Gaia? The European Space Agency (ESA) answers
Quote
Gaia is an ambitious mission to chart a three-dimensional map of our Galaxy, the Milky Way, in the process revealing the composition, formation and evolution of the Galaxy. Gaia will provide unprecedented positional and radial velocity measurements with the accuracies needed to produce a stereoscopic and kinematic census of about one billion stars in our Galaxy and throughout the Local Group. This amounts to about 1 per cent of the Galactic stellar population.
Posted By: Mona - Astronomy Re: Gaia - 05/05/18 08:02 AM
The recent Gaia data release has made astronomical hearts flutter. Gaia is a satellite put in orbit by the European Space Agency (ESA). It's not taking pretty pictures like Hubble, it's been measuring the positions of things. Billions of stars and other objects.

But let's find out about it the easy way. Sit back and let Fraser Cain tell the story. Thanks To Gaia We Now Know Exactly Where 1.7 Billion Stars Are In The Milky Way
Posted By: Mona - Astronomy Re: Gaia - 05/07/18 09:04 AM
Gaia is an ESA mission to survey more than one billion stars in our Galaxy and its local neighbourhood in order to build the most precise 3D map of the Milky Way and answer questions about its structure, origin and evolution.

Cosmic scales covered by Gaia

The new data release pins down the positions of nearly 1.7 billion stars, and with a much greater precision. For some of the brightest stars in the survey, the level of precision equates to Earth-bound observers being able to spot a Euro coin lying on the surface of the Moon. 

With these accurate measurements it is possible to separate the parallax of stars – an apparent shift on the sky caused by Earth’s yearly orbit around the Sun – from their true movements through the Galaxy.

The new catalogue lists the parallax and velocity across the sky, or proper motion, for more than 1.3 billion stars. From the most accurate parallax measurements, about ten per cent of the total, astronomers can directly estimate distances to individual stars.

Gaia also observes objects in our Solar System: the second data release comprises the positions of more than 14 000 known asteroids, which allows precise determination of their orbits. A much larger asteroid sample will be compiled in Gaia’s future releases.

Further afield, Gaia closed in on the positions of half a million distant quasars, bright galaxies powered by the activity of the supermassive black holes at their cores. These sources are used to define a reference frame for the celestial coordinates of all objects in the Gaia catalogue, something that is routinely done in radio waves but now for the first time is also available at optical wavelengths.
Posted By: Mona - Astronomy Re: Gaia - 05/08/18 10:11 PM
Gaia is a mission of the European Space Agency (ESA). Here is ESA's video about Gaia's second data release. The mission has produced an extraordinary catalogue of over one and a half billion stars in our galaxy. Based on observations between July 2014 to May 2016, it includes the most accurate information yet on the positions, brightness, distance, motion, colour and temperature of stars in the Milky Way as well as information on asteroids and quasars.
Posted By: Mona - Astronomy Re: Gaia - 05/12/18 08:51 AM
I've posted videos about Gaia by Canadian Fraser Cain and from ESA with a British accent. Here's How Gaia Changed Astronomy Forever, and if you have a thing for Australian accents, this is one for you.
Posted By: Mona - Astronomy Re: Gaia - 05/17/18 05:28 PM
This image is not blurry. It shows in clear detail that the Large Magellanic Cloud (LMC) rotates. (The LMC is the largest satellite galaxy of the Milky Way.) The rotation of the LMC is presented here with fine data from the Gaia satellite. Gaia measures the positions of stars so accurately that subsequent measurements can reveal slight proper motions of stars not previously detectable. The featured image shows, effectively, exaggerated star trails for millions of faint LMC stars. Inspection of the image also shows the center of the clockwise rotation: near the top of the LMC's central bar. The LMC, prominent in southern skies, is a small spiral galaxy that has been distorted by encounters with the greater Milky Way Galaxy and the lesser Small Magellanic Cloud (SMC).

Image Credit & Licence: ESA, Gaia, DPAC
Explanation: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
© BellaOnline Forums