Earth has an amazing capability to support life, and it’s all because of the mighty sun. If we were off axis by a few meters, then earth could be either too hot or too cold.
But the orientations of the earth made everything just perfect in such a way that water can flow easily, and for other chemicals to exist in certain states, which scientists believe is the cornerstone for life on earth to thrive.
This theory was proposed by the researchers at the University of Cambridge and the Medical Research Council Laboratory of Molecular Biology (MRC LMB). Their study was published in the Science Advances journal.
This brought them to another interesting theory, what if we could find such planets that receive the right amount of UV radiation from the sun in the universe. These specific conditions could support life on other planets.
Hence, the researchers tracked down the planets that have the same living conditions, or closely similar to that found on earth. The main takeaway here is that these planets have the right conditions to maintain water in its liquid form.
Dr. Paul Rimmer, a postdoctoral researcher with a joint affiliation at Cambridge's Cavendish Laboratory and the MRC LMB, and the paper's lead author added, "This work allows us to narrow down the best places to search for life. It brings us just a little bit closer to addressing the question of whether we are alone in the universe."
The new paper concentrates on finding such planets and studying if and how the formation of life takes place. In 2015, another research group led by Professor Sutherland at the MRC LMB proposed that cyanide is one of the greatest accelerators that pave the way for life on earth to take place.
They believe that our earth gained reserves of cyanide when the carbon in the meteorite that hit the prehistoric earth reacted with nitrogen in the atmosphere to form hydrogen cyanide. This hydrogen cyanide rained to the surface and interacted with various materials in the presence of UV light from the Sun to produce compounds that are considered to be the building blocks of life.
So, the researchers made a laboratory setup that would mimic the different ecological situations of the earth. And they gave this setup a UV light source to see what would happen.
Their experiment involved finding out how quickly the building blocks of life are formed through hydrogen cyanide and hydrogen sulphide ions in water when exposed to UV light.
The results showed that the reactions between different elements created RNA, the first molecule the scientists believe to carry information on life. The next set of compounds created in the setup were precursors to lipids, amino acids, and nucleotides, which are again essential components for animal and human cells.
"I came across these earlier experiments, and as an astronomer, my first question is always what kind of light are you using, which as chemists they hadn't really thought about," said Rimmer. "I started out measuring the number of photons emitted by their lamps, and then realized that comparing this light to the light of different stars was a straightforward next step."
They also found that UV light is an excellent accelerator by comparing the results of the experiments which were performed in the presence and absence of light.
They further compared the light chemistry with the dark chemistry against the UV light emitted by different stars and plotted the UV light available to planets that orbit around these stars. This plot determines exact planets where a chemistry to form building blocks of life can be activated.
The new research is aimed at finding such planets that can facilitate conditions for the life to develop.
Estimates show that the universe houses more than 700 million trillion terrestrial planets across space and time. As such, the task of finding such planets is not going to be easy.
“Of course, being primed for life is not everything and we still don’t know how likely the origin of life is, even given favorable circumstances - if it’s really unlikely then we might be alone, but if not, we may have company,” said Sutherland.
But the possibility of finding another lifeform or another earth itself is something that we cannot refrain from trying.