Astronomers from the UK have created a new map of the Milky Way made up of nearly two billion stars using data gathered by the European Space Agency (ESA) Gaia space observatory.
University of Cambridge experts led the creation of the cosmic atlas of two billion stars, that they believe could shed light on how our galaxy came into existence and what might happen to it in the distant future.
The detailed map is based on the most recent data released by the ESA Gaia mission – which has two satellites 930,000 miles from Earth measuring the distance to and between stellar objects throughout the galaxy.
The map and accompanying data will allow astronomers to gain a deeper understanding of our own galaxy, how stars are spread out, how even find stars the most like our own Sun for further, more detailed study in future.
About two billion stars have been examined in detail by the Gaia satellite, including their positions, motion and colour and that data allowed Cambridge researchers to create a detailed 3D map of the Milky Way
This image includes details on more than 1.8 billion stars studied by Gaia since 2013. Brighter regions represent denser concentrations of bright stars, while darker regions correspond to patches of the sky where fewer and fainter stars are found
Cambridge researchers created a 3D map of the Milky Way using data from the latest Gaia release that lets them study the distance to other stars using the Sun as a starting point
The latest release from the Gaia observatory is the most detailed ever catalogue of the stars in the Milky Way – the last release included details on 1.6 billion stars, this brings that up to two billion.
It also includes information on our satellite galaxies – the Large and Small Magellanic clouds and the bridge of stars that link the two stellar bodies.
Dr Floor van Leeuwen, who led the 3D map project at Cambridge, said this tool will become one of the major backbones of modern astrophysics, providing scientists with new ways to study our galaxy in detail.
Launched in 2013, the Gaia satellite operates at the so-called Lagrange 2 (L2) point – a gravitationally stable spot in the Sun-Earth system and measures the position and brightness of stars,a long with their magnitudes and colour.
The primary objective of Gaia is measure stellar distances using the parallax method. In this case astronomers use the observatory to continuously scan the sky, measuring the apparent change in the positions of stars over time, resulting from the Earth’s movement around the Sun.
The Gaia data will also allow astronomers to measure the mass of the Milky Way by analysing the ‘gentle’ acceleration of the solar system as it orbits around the galaxy, according to the European Space Agency.
Two previous releases included the positions of 1.6 billion stars. This release brings the total to just under 2 billion stars, whose positions are significantly more accurate than in the earlier data.
Gaia also tracks the changing brightness and positions of the stars over time across the line of sight (their so-called proper motion), and by splitting their light into spectra, measures how fast they are moving towards or away from the Sun and assesses their chemical composition.
It is thought that over a year the Sun accelerates towards the centre of the galaxy by 7mm per second, while orbiting at a speed of about 124 miles (200 km) a second.
It also includes information on our satellite galaxies – the Large and Small Magellanic clouds and the bridge of stars that link the two collections of stellar bodies
Gaia’s Early Data Release 3 was made public on 3 December 2020. It contains detailed information on more than 1.8 billion sources, as measured by the Gaia spacecraft
Astronomers will also be able to deconstruct the two largest companion galaxies to the Milky Way – the Small and Large Magellanic Clouds – using the data from Gaia.
The two galaxies are connected by a bridge of stars thought to be 75,000 light years long, according to researchers examining the new data.
Dr Caroline Harper, head of space science at the UK Space Agency, which provided the funding for the research, said Gaia has allowed for the creation of the most detailed billion-star 3D atlas ever assembled.
‘For thousands of years, we have been preoccupied with noting and detailing the stars and their precise locations as they expanded humanity’s understanding of our cosmos,’ Harper said.
‘Gaia has been staring at the heavens for the past seven years, mapping the positions and velocities of stars.’
The data will also include ‘exceptionally accurate’ measurements of the 300,000 stars that are relatively close to the Sun, within a distance of 326 light years.
The researchers aim to use the information to learn more about the fate of the Milky Way by predicting how the galaxy will change in the next 1.6 million years.
WHAT IS THE EUROPEAN SPACE AGENCY’S GAIA PROBE AND WHAT IS DESIGNED TO DO?
Gaia is an ambitious mission to chart a three-dimensional map of our galaxy, the Milky Way, and in the process reveal its composition, formation and evolution.
Gaia has been circling the sun nearly a million miles beyond Earth’s orbit since its launch by the European Space Agency (ESA) in December 2013.
On its journey, the probe has been discreetly snapping pictures of the Milky Way, identifying stars from smaller galaxies long ago swallowed up by our own.
Tens of thousands of previously undetected objects are expected to be discovered by Gaia, including asteroids that may one day threaten Earth, planets circling nearby stars, and exploding supernovas.
Artist’s impression of Gaia mapping the stars of the Milky Way. Gaia maps the position of the Milky Way’s stars in a couple of ways. It pinpoints the location of the stars but the probe can also plot their movement, by scanning each star about 70 times
Astrophysicists also hope to learn more about the distribution of dark matter, the invisible substance thought to hold the observable universe together.
They also plan to test Albert Einstein’s general theory of relativity by watching how light is deflected by the sun and its planets.
The satellite’s billion-pixel camera, the largest ever in space, is so powerful it would be able to gauge the diameter of a human hair at a distance of 621 miles (1,000 km).
This means nearby stars have been located with unprecedented accuracy.
Gaia maps the position of the Milky Way’s stars in a couple of ways.
Gaia’s all-sky view of our Milky Way Galaxy and neighbouring galaxies, based on measurements of nearly 1.7 billion stars. The map shows the total brightness and colour of stars observed by the ESA satellite in each portion of the sky between July 2014 and May 2016. Brighter regions indicate denser concentrations of especially bright stars, while darker regions correspond to patches of the sky where fewer bright stars are observed. The colour representation is obtained by combining the total amount of light with the amount of blue and red light recorded by Gaia in each patch of the sky.
It pinpoints the location of the stars but the probe can also plot their movement, by scanning each star about 70 times.
This is what allows scientists to calculate the distance between Earth and each star, which is a crucial measure.
In September 2016, ESA released the first batch of data collected by Gaia, which included information on the brightness and position of over a billion stars.
In April 2018, this was expanded to high-precision measurements of almost 1.7 billion stars.