 |
| The Gaia satellite collected the data on some 1.7 billion stars from its unique vantage point in space about 1.5 million kilometres (930,000 miles) from Earth (AFP Photo) |
Paris (AFP)
- Europe's Gaia satellite has produced a 3-D map, hailed as revolutionary, of
more than a billion stars in our Milky Way galaxy -- complete with their
distance from Earth, colour, and motion through space.
The
eagerly-anticipated catalogue, published Wednesday, was compiled from data Gaia
gathered on some 1.7 billion stars from its unique vantage point in space,
about 1.5 million kilometres (930,000 miles) from Earth.
"The
dataset is very rich and we believe it will revolutionise astronomy and our
understanding of the Milky Way," Gaia's scientific operations manager Uwe
Lammers told AFP of the massive data release.
"This
catalogue is the most precise, most complete catalogue that has ever been
produced. It allows studies which have not been possible before."
Launched in
2013, Gaia started operating the following year, gathering data on 100,000
stars per minute -- some 500 million measurements per day. Its first map was
published in September 2016, based on a year's worth of observations of about
1.15 billion stars.
An update,
launched at the ILA international air and space show in Berlin, adds stars and
provides more data on each one, from measurements taken over 22 months in
2014-2016.
Some stars
were measured as many as 70 times as the satellite, co-rotating with Earth
around the Sun, continuously scanned the galaxy.
"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," said an ESA statement.
The new,
improved map depicts 1.7 billion stars "for which we can tell where they
are in the sky with very high accuracy, and how bright they are," said
Anthony Brown of the Gaia Data Processing and Analysis Consortium.
For 1.3
billion of those, "we know their distance and we know how they move
through space."
There is,
furthermore, information on the radial velocities of some seven million stars
-- indicating the rate at which they are moving towards, or away from, Earth.
Opening a
chocolate box
With all
this data, "we can make a map of the whole night sky," said Brown,
who described the end result as "stunning".
"You
see the whole Milky Way in motion around its axis."
Gaia also
revealed the orbits of some 14,000 "solar system objects" -- mapped
as an intricate spiderweb of space rocks shooting around the Sun.
"It
represents the most accurate survey ever of asteroids in the Solar
System," said Brown. More will be added in future updates.
Information
sent to Earth by Gaia is collated by 450 scientists from 20 countries.
One of
them, Antonella Vallenari, likened the data release to "opening a
chocolate box".
"It's
very, very exciting," she said at the launch event in Germany, webcast
live.
The full
data will be published in a series of scientific papers in a special issue of
the journal Astronomy & Astrophysics, laying the foundation for decades of
further study.
"We
are really getting today the catalogue of a billion stars zipping through the
Milky Way in various directions," said Guenther Hasinger, ESA's director
of science.
"With
Gaia, we can actually deconstruct the whole history of the Milky Way," he
added. "It's like archaeoastronomy... to really build up the history of
our Universe."
Lammers
said another update is due in 2020.
No comments:
Post a Comment