The first accurate 3D map of galaxy unveiled
Published : Tuesday, 5 February, 2019 at 4:35 PM Count : 602
Astronomers have uncovered the true twisted nature of our galaxy, the Milky Way.
Until now, the galaxy was generally thought to be a flat spiral consisting of an estimated 250 billion stars.
The sun and its planets, including the Earth, occupy an insignificant spot in one of the minor spiral arms, daily Mail reports.
But a new study has shown that in reality the Milky Way is warped.
It becomes increasingly twisted the further away stars are from the galactic centre.
The warping is thought to be caused by torque from the spinning galaxy's densely packed inner disc of stars.
Professor Richard de Grijs, one of the astronomers from Macquarie University in Sydney, Australia, said: 'We usually think of spiral galaxies as being quite flat, like Andromeda, which you can easily see through a telescope.'
The scientists updated a 3D map of the Milky Way using 1,339 large pulsating stars, each up to 100,000 times brighter than the sun.
The so-called Cepheid stars are used as 'standard candles' by astronomers to estimate galaxy-wide distances.
The Milky Way's twists are rare but not unique, say the scientists, whose findings are published in the journal Nature Astronomy.
They have observed a dozen other galaxies which show similar progressively twisted spiral patterns in their outer regions.
Classical Cepheids are young stars that are some four to 20 times as massive as our Sun and up to 100,000 times as bright.
Such high stellar masses imply that they live fast and die young, burning through their nuclear fuel very quickly, sometimes in only a few million years.
They show day- to month-long pulsations, which are observed as changes in their brightness.
Combined with a Cepheid's observed brightness, its pulsation period can be used to obtain a highly reliable distance.
Prof de Grijs said: 'Somewhat to our surprise, we found in 3D our collection of 1,339 Cepheid stars and the Milky Way's gas disc follow each other closely.
'This offers new insights into the formation of our home galaxy.
'Perhaps more importantly, in the Milky Way's outer regions, we found the S-like stellar disc is warped in a progressively twisted spiral pattern.'
The map sheds fresh light on the evolution of the galaxy - and also shows the warped disc also contains young stars.