We may already have evidence of extraterrestrial life, but no way to say that is what it is, scientists claim
Evidence for life on other planets may already be on a hard drive on Earth, but we may not realize that that is what it is, claims a science philosopher.
The question of whether we are ‘alone in the universe’ has been thought about for generations by scientists, writers, and philosophers.
Dozens of missions have been launched to search for life outside the earth and authors have written numerous books on the subject.
Professor of scientific philosophy, Dr. Peter Vickers, from the University of Durham, says that scientists must have an open mind when considering life elsewhere.
In an article for The conversation, he says conventional thinking or a bias towards life, because we know it can go wrong with an important discovery.
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They may not be little green men, but scientists must have an open mind when considering life elsewhere in the universe, says professor of scientific philosophy, Dr. Peter Vickers
“Many breakthroughs happen by accident, from the discovery of penicillin to the discovery of the cosmic microwave background radiation left over from the Big Bang,” the philosophy professor said in the article.
‘These often reflect a certain degree of happiness on behalf of the researchers involved. When it comes to extraterrestrial life, is it enough to assume that we will know when we see it?
One of the techniques that scientists can use to identify extraterrestrial life is to search for biosignatures – that is any substance that provides scientific evidence of past life.
It can be an element, isotope or molecule that needs life to be present in a certain environment.
“In recent years, there have been changes in our theories about what counts as a biosignature and which planets can be habitable, and further reversals are inevitable,” said Dr. Vickers.
“But the best thing we can really do is interpret the data we have with our current best theory, not with a future idea that we haven’t had yet.”
A recent study found that it is common for distant exoplanets to have water in their atmosphere around distant stars.
Scientists from the University of Cambridge have searched the composition of 19 worlds for five years and discovered that water is often seen, but in small quantities.
A total of 14 of these worlds had water vapor in the atmosphere and the major chemicals sodium and potassium were present in six.
It is vital that researchers approach every future quest for life with an open mind and are willing to discover ‘the unexpected’, he wrote.
“Studying the universe largely unscathed from the theory is not just a legitimate scientific undertaking – it’s a crucial one.”
There are many of the world in the universe, so the probability that alien species will develop, at the microbial level, is very high, astronomers say.
One of the most famous images from the Hubble Space Telescope is from nearly 10,000 galaxies in a small part of the night sky, the Hubble Ultra Deep Field.
In each of the galaxies there are on average about 100 million stars and each star probably has at least one planet, according to exoplanet researchers.
The most comprehensive overview of atmospheric chemical compositions of exoplanets to date has revealed trends that challenge current theories about planet formation and have shown that water is common but scarce on extraterrestrial worlds.
Space agencies are launching ever more sensitive instruments in search of exoplanets and extraterrestrial life in those distant galaxies and in our own galaxy.
Some even hunt much closer to home.
There are four missions launched this year to Mars and three of which have the hunt for life on the Red Planet as a primary objective.
Missions are also planned to search the giants of the gas giants and hunt telescopes on planets in the habitable zone of other stars.
An example is NASA’s planned $ 7 billion HabEx telescope launched in the 2030s on a 10-year search for a “second earth” in the Milky Way.
The European Space Agency has launched its Cheops satellite that will hunt habitable planets and NASAs will find exoplanets since 2018.
With the discovery of more than 3,500 exoplanets, and another one found every day, the search for life has begun to move away from the solar system.
There are dozens of ‘potentially habitable planets’ in orbit around extraterrestrial stars – when they are looking for those in a similar position to the earth and with an earth-like makeup.
This display of nearly 10,000 galaxies is called the Hubble Ultra Deep Field, it is a small area of space and in each of the galaxies there are on average about 100 million stars and each star probably has at least one planet, according to exoplanet researchers
Dr. Vickers says that scientists should consider a broader approach to the search.
“In the search for extraterrestrial life, scientists must be completely open-minded,” he said in the article.
“This means a certain encouragement for non-regular ideas and techniques.”
He said that every new exoplanet discovered by scientists is rich in physical and chemical complexity.
‘It is all too easy to propose a case where scientists do not double check a target marked as’ lack of meaning’.
“Its great significance, however, would be recognized by further analysis or by a non-standard theoretical approach.”
He says that we must be prepared to search in unexpected places and to adopt a less rigid approach when looking for life elsewhere in the universe.
“One thing I learned after spending more than 20 years in this field of exoplanets is the unexpected expectation,” said Scott Gaudi of Nasa’s advisory board.
“The only way to know for sure if they have life is to go outside and look.”
HOW SCIENTISTS STUDY THE ATMOSPHERE OF EXOPLANETS?
Distant stars and their rotating planets often have different circumstances than everything we see in our atmosphere.
To understand this new world, and what they are made of, scientists must be able to detect what their atmosphere consists of.
They often do this using a telescope similar to Nasa’s Hubble telescope.
These huge satellites scan the sky and hold onto exoplanets that NASA may find interesting.
Here the on-board sensors perform various forms of analysis.
One of the most important and useful is called absorption spectroscopy.
This form of analysis measures the light that comes from the atmosphere of a planet.
Each gas absorbs a slightly different wavelength of light, and when this happens, a black line appears on a full spectrum.
These lines correspond to a very specific molecule, indicating that it is present on the planet.
They are often called Fraunhofer lines after the German astronomer and physicist who first discovered them in 1814.
By combining all the different wavelengths of light, scientists can determine all the chemicals that form the atmosphere of a planet.
The key is that what is missing gives the clues to find out what is present.
It is vital that this is done by space telescopes, because then the Earth’s atmosphere would interfere.
Absorption by chemicals in our atmosphere would warp the sample, so it is important to study the light before it has had the chance to reach the earth.
This is often used to search for helium, sodium and even oxygen in alien atmospheres.
This diagram shows how light passing through a star and the atmosphere of an exoplanet produces Fraunhofer lines that indicate the presence of important compounds such as sodium or helium