22 November 2020
American astronomers say new evidence supports the idea that a large telescope on the moon could study the oldest stars in the universe.
A group of international scientists proposed the idea to build such a telescope to NASA in 2008. The U.S. space agency looked into the plan, but later decided against it. NASA said not enough supporting science on the earliest stars existed at the time.
Now, a group of astronomers at the University of Texas at Austin say they have found new evidence that a telescope on the moon would be able to gather data on the first stars in the universe. The team, led by NASA Hubble Fellow Anna Schauer, is set to publish their research results in an upcoming issue of The Astrophysical Journal.
The researchers named the device Ultimately Large Telescope. It would operate with a 100-meter mirror made out of liquid. It could receive power from a solar power collection station on the moon and send data to a satellite in lunar orbit.
A mirror made of liquid is lighter than a glass one and less costly to transport to the moon. The astronomers say the liquid would include metallic material for effective reflection.
The team is proposing that the telescope could be placed inside a crater at the moon's north or south pole. The device would study the first stars by centering on the same area of sky continuously, in an effort "to collect as much light from them as possible," the scientists said in a statement.
The first stars in the universe are believed to have formed more than 13 billion years ago. The stars are thought to have formed after the Big Bang – the large explosion that many scientists believe created the universe.
The team says these stars were born out of a mix of hydrogen and helium gas. They are likely 10 to 100 times larger than our sun.
Volker Bromm is a professor at the University of Texas at Austin and a leader of the project. "We live in a universe of stars," he said in a statement. But an important remaining question is "how star formation got going early in cosmic history," he added.
The scientists say their moon-based observer would be able to gather data on the oldest stars, which no other telescope is equipped to do.
NASA has plans to send the James Webb Space Telescope, its newest telescope, to space in October 2021. The launch of the James Webb has been delayed many times.
NASA says the telescope is designed to look deeper into space and offer more answers about the past than any other spacecraft. It is a large infrared telescope, with a nearly seven-meter mirror for exploring space.
Bromm said that throughout the history of astronomy, telescopes have become more and more powerful, permitting exploration of times closer to the Big Bang. He added that the James Webb Space Telescope is expected to reach the time when galaxies first formed.
"But theory predicts that there was an even earlier time, when galaxies did not yet exist, but where individual stars first formed," Bromm said. "This moment of 'very first light' is beyond the capabilities even of the powerful (James Webb), and instead needs an ‘ultimate' telescope."
The team is proposing that the world astronomy community revisit the plan to use a lunar liquid-mirror telescope as a way to directly observe these early stars for the first time.
I'm Bryan Lynn.
Reuters reported on this story. Bryan Lynn adapted the report for VOA Learning English. Ashley Thompson was the editor.
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Words in This Story
lunar – adj. relating to the moon
reflect – v. to send back or bounce off
crater – n. a large round hole in the ground made by the explosion of a bomb or by something falling from the sky
pole – n. the part of a body, such as Earth, that is furthest north or south
cosmic – adj. relating to the whole universe
infrared – n. technical: producing or using rays of light that cannot be seen and that are longer than rays that produce red light
galaxy – n. a large group of stars from the same universe
capability – n. the ability or power to do something
ultimate – adj. the final or most important