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Can NASA's James Webb telescope detect extraterrestrial life?

via:博客园     time:2018/9/18 10:06:27     readed:327


James · Webb Telescope has some new technologies that have never been used in space.

Sina Technology News, Beijing time on September 18th news, according to foreign media reports, if NASA's James · Webb telescope can be launched in 2021 as planned, has been 14 years later than originally scheduled. But when it enters the orbit and rotates around the sun 1.5 million kilometers from the Earth, it will revolutionize astronomy.

NASA is proud to say that James · Weber Telescope can "look back at the past and take us through the first galaxies formed in the early universe." If this is not bold enough, the telescope, as the successor to the Hubble telescope, has another great talent: scientists may be able to use it to look for signs of alien life and detect whether the planet's atmosphere around the stars is alien. The existence of life has changed.

Despite this, this project was almost cancelled by the US government in 2011. This is largely related to its high cost. The telescope was originally estimated to cost $1 billion, but it has now become $10 billion. But astronomers (including the University of Washington team that used the telescope to detect life) were excited about the launch.

How to detect life on distant planets?

University of Washington astronomer Joshua · Joshua Krissansen-Totton and his team examined the James · Weber telescope to analyze whether the telescope could be in the atmosphere of a planet near the stars. The so-called "biomarker" was detected.

“We can conduct such observations and detect signs of life in the next few years. ” Crisson · Toton said.


The basis of this research is that James · the Webb telescope is very sensitive to light, so it can identify the so-called "atmospheric chemical imbalance" phenomenon. This term may not be well remembered, but it has been around for a long time, first proposed by famous scientists James · James Lovelock and Carl · Carl Sagan. The principle is that if all the life on the earth suddenly disappears tomorrow, the natural chemical reactions will occur in all kinds of gases that make up the atmosphere, and the chemical composition of the atmosphere will change slowly, which is different from the original state of living and discharging various exhaust gases. getting bigger.

Therefore, the search for oxygen (or its "chemical close relatives") has always been seen as a good way to find extraterrestrial life. But this is based on the premise that extraterrestrial life follows the same biological mechanisms as humans. But the truth may not be the case. Therefore, assessing the atmospheric chemical imbalance of the planet, that is, assessing the degree of deviation of a certain planet's atmosphere from the “normal state”, may be the key to finding extraterrestrial life.

The chemical composition of the planet's atmosphere that orbits other stars can be measured by light: When the planet moves into the middle of the Earth and its central star, carefully measure the slight attenuation of the stellar light. Gases in the planet's atmosphere cause the amount of light to change with the wavelength of the light (ie, color), helping us understand the content of various chemical elements in the atmosphere.

What is the best observation object?

Crissanson · Todton simulated James · Weber telescope if you observe the data that TRAPPIST-1 may obtain. This star is about the size of Jupiter, about 39.6 light years from the Sun. In 2017, scientists discovered that there were seven Earth-sized planets around TRAPPIST-1, which caused a sensation. Some of them also have liquid water, so there is a good chance of extraterrestrial life.

Researchers at the University of Washington predict that the James · Weber telescope can measure methane and carbon dioxide in the atmosphere of the fourth planet, TRAPPIST-1e, based on the extent of light attenuation in the wavelength range affected by methane and carbon dioxide. Such traces are so faint and unimaginable that measurement is extremely difficult. But Cornell University astronomer Jonathan · Prof. Jonathan Lunine was very excited about this prediction, saying that James · Webb Telescope can really do this. ”


If life on Earth suddenly disappears, the Earth's atmosphere will also change.

But Crissanson · Toton pointed out that after this measurement task is completed, we have to ask a question: Is there an abiotic process that produces the same effect? Planetary atmospheres, including the Earth's atmosphere, can also be altered by abiotic processes such as volcanic eruptions. Therefore, if we find that the atmospheric composition of TRAPPIST-1e is abnormal, we must first eliminate all abiotic effects before we can declare the existence of extraterrestrial life on the planet.

Crissanson · Toton said: "To confirm this, multiple observations are needed to make this discovery board nailed. However, if we detect an abnormal situation and can't find other explanations, it will be an extremely exciting discovery. ”

Which other institutions will conduct such research?

Currently, James · Webb Telescope's golden mirror is still safely locked in a laboratory in California. To explore the above possibilities, astronomers still have to wait.

In addition, the telescope will work with a range of new devices to investigate the planets around other stars in the next few decades.

Researchers are preparing to build huge ground-based telescopes in Hawaii and Chile. The ESA-led Ariel mission of the European Union will also be carried out in the late 1920s to examine the stellar atmosphere around other stars.

Professor Lu Ning said: "I think we are in a good time to understand the universe and explore space, and the next step will be done by James · Weber Telescope. It will definitely be worth the money. ”

Prof. Gillian Wright, the chief scientist of the mid-infrared instrumentation team led by the UK on the telescope, agrees with this: “We have never had the ability to carry out such a feat in space before.” To say that a telescope will open up a new window for us to understand the universe, this statement may be very old-fashioned, but for James · Weber telescope, this is true. ”

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