Nearly 1.7 billion stars have been plotted in unprecedented detail with highly anticipated release of data from the European Space Agency's Gaia spacecraft. The $1 billion (750 million euros) Gaia spacecraft launched in 2013 for a five-year mission to map the night sky with unmatched accuracy.
The spacecraft is placed far beyond the moon's orbit, in the Lagrange-2, or L2, point, a gravitationally stable spot about 1 million miles (1.5 million kilometers) away from Earth. Unlike space telescopes such as Hubble that orbit the Earth, Gaia can scan the cosmos without Earth blocking a large chunk of its view.
As it rotates in space, Gaia measures about 100,000 stars each minute and covers the whole sky in about two months. Each star is measured 70 times on an average. Gaia launched in 2013, and released their first batch of data in September 2016. Those data included distances and motions of roughly 2 million stars; the new data up that number to 1.3 billion.
The Gaia mission also examines the brightness, colors and surface temperatures of some stars, and the amount of space dust between us and them. Looking beyond stars, the data includes the positions of over 14,000 asteroids. While 1.7 billion stars may be hard to wrap your head around, NASA says scientists estimate there are at least 100 billion stars (and maybe as many as 400 billion) in the Milky Way alone.
By: Swati Kaushal