NASA's James Webb telescope successor of the Hubble telescope

If NASA’s James Webb telescope can be launched in 2021 as planned, it is 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 the James Webb 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 has some alien life which will change the existence of life.

Despite this, this project was almost canceled 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 proposed “using the telescope to detect life”) were thrilled by the launch plan.

NASA’s James Webb Space Telescope — Credit: Northrop Grumman

How James Webb telescope detects life on distant planets?

University of Washington astronomer Joshua Krissanson Toton and his team examined the James Webb telescope to analyze whether the telescope could detect so-called “biomarkers” in the atmosphere of planets adjacent to the stars. “We can carry out such observations and detect signs of life in the next few years,” said Krissanson Toton.

The basis of this research is that the James 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 Lovelock and 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 slowly change, which is different from the original state of living and discharging various exhaust gases, getting bigger.

Therefore, the search for signs of oxygen (or its “chemical close relatives” of ozone) 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 in the 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.

James Webb telescope illustration — Credit: NASA

What is the best observation object?

Krissanson Todton simulated the data that the James Webb telescope could obtain if it observed TRAPPIST-1. This star is about the size of Jupiter, about 39.6 light years from the Sun. In 2017, scientists discovered that there are 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 Webb telescope can measure methane and carbon dioxide in the atmosphere of the fourth planet, TRAPPIST-1e, based on the attenuation of light in the wavelength range affected by methane and carbon dioxide. Such traces are so faint and unimaginable that measurement is extremely difficult. But Professor Jonathan Luning, an astronomer at Cornell University, was very excited about this prediction, saying that “The James Webb telescope can really do this.”

However, Krissanson Toton pointed out that after this measurement task is completed, we must first 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 extraterrestrial life on the planet.

Krissanson Toton said: “To confirm this, we need to make multiple observations to make this discovery board. However, if we detect an abnormal situation and can not find other explanations, this will be once Very exciting discovery.”

Which other institutions will conduct such research?

Currently, the golden mirror of the James Webb telescope 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.

Professor 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 it just a telescope but will open us a way to understand the universe. The new window, this statement may be very old-fashioned, but for the James Webb telescope, this is true.”