Warp factor: Milky Way turns out to have a twist
The spinning spiral galaxy that is the sun’s home is bent towards its edges, astronomers have discovered.
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.
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.
We usually think of spiral galaxies as being quite flat, like Andromeda, which you can easily see through a telescope Professor Richard de Grijs
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.