1st Sky Map

Gaia

Exciting!

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I don't understand this statement about "What does Gaia see?" I thought our solar system was on the outskirts. How could the sun do this?:

The Sun moves around the centre of the Milky Way at a speed of about 220km/second (10,000,000,000 miles/hour)

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The mind is a weird and mysterious place

I don't understand this statement about "What does Gaia see?" I thought our solar system was on the outskirts. How could the sun do this?:

[quote]The Sun moves around the centre of the Milky Way at a speed of about 220km/second (10,000,000,000 miles/hour)

[/quote

ESA’s Gaia satellite


more info:


Gaia's first galaxy map

The astronomy world is abuzz today because of ESA's announcement of the first release of data from the Gaia mission. Gaia is a five-year mission that will eventually measure the positions and motions of billions of stars; this first data release includes positions for 1.1 billion of them, and proper motions for 2 million. The map below does not show all 1.1 billion stars; rather it's a map of the density of stars that Gaia has measured so far, with brighter areas corresponding to more stars.

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I don't understand this statement about "What does Gaia see?" I thought our solar system was on the outskirts. How could the sun do this?:

[quote]The Sun moves around the centre of the Milky Way at a speed of about 220km/second (10,000,000,000 miles/hour)

[/quote

ESA’s Gaia satellite


more info:


Gaia's first galaxy map

The astronomy world is abuzz today because of ESA's announcement of the first release of data from the Gaia mission. Gaia is a five-year mission that will eventually measure the positions and motions of billions of stars; this first data release includes positions for 1.1 billion of them, and proper motions for 2 million. The map below does not show all 1.1 billion stars; rather it's a map of the density of stars that Gaia has measured so far, with brighter areas corresponding to more stars.

Yes, but that still doesn't really answer my question.

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The mind is a weird and mysterious place

As the Earth goes around the Sun, relatively nearby stars appear to move against the "fixed" stars that are even further away
Because we know the Sun-Earth distance, we can use the parallax angle to work out the distance to the target star
But such angles are very small - less than one arcsecond for the nearest stars, or 0.05% of the full Moon's diameter
Gaia will make repeat observations to reduce measurement errors down to seven micro-arcseconds for the very brightest stars
Parallaxes are used to anchor other, more indirect techniques on the 'ladder' deployed to measure the most far-flung distances

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1st Sky Map

Gaia

Fascinating!

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