(ORDO NEWS) — Thanks to the fortunate location of a massive cluster of galaxies, astronomers have discovered a single star, located almost at the opposite end of the universe.
This marked the discovery of the most distant single star in the history of science. The mass of a star can be 500 times the mass of the Sun.
Almost all the stars we see in the night sky are from our own Milky Way galaxy. Even with the most powerful telescopes, under normal conditions, individual stars can only be seen in the galaxies closest to us. In general, distant galaxies are observed as mixed light from billions of stars.
However, using a unique natural phenomenon known as “gravitational lensing,” astronomers led by Brian Welch of Johns Hopuins University, USA, were able to detect a star at such a huge distance that it is usually difficult to see an entire galaxy.
According to one of the predictions of Einstein’s General Theory of Relativity, mass can warp space itself. When light passes near a massive object, it travels through curved space and changes direction.
If a massive object lies in the path between us and a more distant light source, then that object can deflect and focus light in our direction, like a lens, increasing the intensity of the light emitted by the distant source.
Typically, the apparent size of a galaxy is increased by several times using this method. However, in the new study, Welsh and his team observed the amplification of light from a single star as it passed through massive galaxy cluster WHL0137-08 along the way. As a result, an increase in the brightness of the source by thousands of times was observed.
The use of this gravitational lens allowed scientists to detect this distant star in 9 hours of observations using the Hubble Space Telescope.
Astronomers gave this star the name Earendel. According to the authors, the star has a mass of about 50 solar masses, and its brightness exceeds the brightness of our star by millions of times.
The star belongs to the early Universe – its light was emitted when the age of our world was no more than one billion years.
At that time, it took light only 4 billion years to reach the protogalaxy Milky Way, but since then the universe has expanded significantly, and in total, light has traveled a huge distance of 18 billion light years, the authors explained.
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