Anti-glare for telescopes to find life beyond Earth

NASA's Starshade project can detect signs of extraterrestrial life hidden by light from stars, thanks to anti-glare devices for telescopes.

Anti-glare project for telescopes

The fact that thousands of planets outside the solar system have been discovered over the past few years has increased the likelihood of one of them having life, possibly even the existence of a "twin" planet with Earth.

"Rather than doubting whether there are planets that exist outside the Earth we have turned to searching for life on these planets," said Nick Siegler, head of the Aviation Agency's Planetary Exploration Program team. US Universe (NASA) . "It is a huge change in NASA's view of finding life."

The wings of the Starshade are being installed in the United States.(Photo: NASA).

However, discovering life millions of kilometers away is not easy, especially if life there has not reached a certain level of intelligence. Sara Seager, a scientist looking for signs of life on the second Earth at the Massachusetts Institute of Technology (MIT), believes the key is to carefully study the atmospheres of potential planets.

One of the technologies that can help researchers like Seager achieve the goal is a strange petal-shaped device called a Starshade.

Simulate Starshade's activity outside the universe:

According to the BBC, a star like the Sun has a light intensity of 10 billion times that of an Earth-sized planet. If the planet needs to be observed near a star like that, we can almost see light directly from the star.

The only hope for astronomers is to prevent light from such a star, allowing the telescope to observe light directly from the planets themselves.

This is a completely different strategy than the way astronomers used it. Because of direct light from distant distant planets, the current observation technique is indirect exploration - for example by detecting changes in light from stars when a planet goes. Pass ahead of it or by measuring the vibrations of stars when the gravity of a planet impacts it.

Test the Starshade microcosm in the desert.(Photo: Northrop Grumman).

Starshade is a giant parachute in space designed to block light from stars, helping telescopes to avoid glare from these stars into planets. So that we can see signs of life if they exist on planets.

"If we want to search for life outside of the Earth, we must build the Starshade," Seager said. With Starshade, scientists hope to determine the composition of the planets' atmosphere, and discover elements that show the presence of life - like oxygen, which accounts for 20% of the atmosphere. Earth's book.

"Oxygen is considered an important biomarker. If there is no life - plants or photosynthetic bacteria - we will see almost no oxygen , " Seager said. However, to determine the biological origin of each element is still a challenge, because life on Earth produces all kinds of gases, and alien life may be more diverse.

Although there are no signs of extraterrestrial life, astronomers have discovered several atmospheres exist. When a planet passes in front of a nearby star, starlight passes through the gas surrounding the planet. The molecules in the atmosphere absorb specific wavelengths of light, depending on each element. By measuring the absorption wavelength, astronomers can determine the composition of the atmosphere.

Large telescopes like the James Webb space telescope, expected to be released in 2018, allow observations of these changes and may help to study the planets' atmosphere even more. Biological indicators can be detected. But this method is only good for planetary systems around small stars known as dwarfs. When a big star like the Sun appears next to the planets, big telescopes like James Webb still don't have. many effects. That's why astronomers like Seager want the Starshade project to come true.

Install Starshade in the laboratory:

As planned, the Starshade will be launched into space with a telescope. When it reaches the predetermined position, it will expand to a diameter of 34m. Petals, shaped like razor blades, will eliminate the effect of diffraction. The Starshade and telescope will then split at a distance of about 50,000km - nearly four times the diameter of the Earth.

This is not easy and researchers have done similar experiments in the desert to verify. Jeremy Kasdin of Princeton University, a member of the Starshade project, is also conducting lab tests with a miniature model with a 5cm Starshade. If the project gets enough funding and everything goes smoothly, NASA can start Starshade as early as 2026.

"We see no problems with the Starshade project," Kasdin said.

A distant bright spot is designed to simulate a star.(Photo: Northrop Grumman).

But Starshade is not the only way to remove the powerful light from the stars. The Starshade project can coincide with WFIRST , a next-generation space telescope. WFIRST is equipped with a tool called coronagraph, which eliminates the light of the star inside the telescope.

"We want to have many approaches in case one of the two ways is not effective," Siegler said.

Coronagraph is an experimental technology first developed in the 1930s to study the sun's crust. According to Siegler, this technology is not ready. Coronagraphs are a complex and fragile device, sensitive to the heat from the Sun or vibrations from mechanisms inside the telescope. For some reason, the light from the stars entering the light sensor will make many observations.

With Starshade, the light is shining from the stars that never reach the telescopes. Instead of giant telescopes, we show a telescope that is relatively simple, cheaper and easier to install. In addition, Starshade may not even need a private telescope, but can be combined with WFIRST. Both Siegler and Kasdin believed in a day not far from the evidence concealed within the light from the stars that would soon reveal the answer to extraterrestrial life.