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Credit: ESA/Hubble & NASA
We live in a golden age for research into space. Scientists collect massive amounts of new information and scientific knowledge at a record pace. But the ancient question remains unanswered: are we alone?
New telescopic technologies, including room -based tools such as the James Webb Telescopehave made it possible for us to discover thousands of potentially habitable exoplanets that could support life similar to that on earth.
Gravitational waves detectors have opened a new option to explore space by capturing space -time distortions that were disappointed by black holes and supernovae.
Commercial space company have further accelerated this progress, which led to increasingly sophisticated space and reusable rockets, which means a new era in space research.
The Osiris Rex mission of NASA Successfully accepted on asteroid Bennu when it was 207 million miles away from the earth and brought back rock and dust samples.
Several countries have developed the ability to absorb robots the moon And Mars with plans to send people to these celestial bodies in the future.
A central driver of all these ambitious efforts is still the basic question of whether life exists elsewhere in the universe or ever exists.
Define life
Planet Earth, as can be seen from space on a black background. | Credit: NASA/NOAA
Defining life is surprisingly challenging. While we intuitively recognize living organisms as life, a precise definition remains difficult to understand. Dictionaries offer various descriptions, such as the ability to grow stimuli, reproduce and react to stimuli.
But these definitions can also be ambiguous.
A more comprehensive definition sees life as a self -supporting chemical system that processes information and maintains a state with low entropy with a low disorder or randomness.
Living beings constantly require energy to maintain their molecular organization and maintain their highly organized structures and functions. Without this energy, life would quickly fall back into chaos and decay. This definition includes the dynamic and complex nature of life and emphasizes its ability to adapt and develop.
Life on Earth, as we currently understand, is based on the interaction of DNA, RNA and proteins. DNA serves as a blueprint of life and contains the genetic instructions required for the development, survival and reproduction of an organism. These instructions are converted into messages that manage the production of proteins, the work horses of the cell, which are responsible for a variety of functions.
This complicated system of DNA replication, protein synthesis and cellular processes – all based on long molecules associated with carbon atoms, is of fundamental importance for life on earth. However, the universe can accommodate life forms based on completely different principles and biochemistry.
Something different from carbon
An illustration of a large rock that is red red by heat and flies through the room towards the earth, with stars in space in the background. | Credit: European space agency
Life elsewhere could use different elements than building blocks. Silicon with its chemical similarities with carbon, was proposed as a potential alternative.
If you exist, life forms on a silicon basis can have unique properties and adjustments. For example, you could use supporting structures based on silicon, which are analogous to bones or bowls in carbon-based organisms.
Although organisms based on silicon have not yet been found on Earth, silicon plays an important role in many existing forms of life. It is an important secondary component for many plants and animals that serve structural and functional roles. For example, diatoms, a kind of algae in the ocean, have glassy cell walls made of transparent silicon dioxide.
This does not make diatomes on silicon base forms, but it proves that silicon can actually act as a component of a living organism. But we still don’t know whether life forms on a silicon basis exist at all. Or what they would look like.
The origins of life on earth
A look at the night sky with a starry sky in the background and many meteors that fly through the atmosphere and appear as white lines, with trees and plant life in the foreground. | Credit: Kenneth Brandon
There are competing hypotheses about how life on earth was created. One of them is that life buildings were in life delivered on or in meteorites. The other is that these building blocks spontaneously came together by geochemistry in the early surroundings of our planet.
Meteorites were indeed found to wear organic moleculesIncluding amino acids that are essential for life. It is possible that organic molecules were formed in the deep room and then brought to earth by meteorites and asteroids.
On the other hand, geochemical processes in the early earth, such as B. those who appear in Warm little ponds Or the necessary conditions and ingredients for life could also be delivered deep in the ocean in hydrothermal ventilation.
However, it was not yet able to present a comprehensive, specific path to the formation of RNA, DNA and the first cellular life on earth.
Many biological molecules are chiral, which means that they exist in two forms that are mirror images from each other like left and right hands. While both left and right -handed molecules are typically produced in the same quantities in the same amount, recent analyzes of meteorites have shown a slight asymmetry that prefers the left -handed form by up to 60 percent.
This asymmetry in spatially derived organic molecules is also observed in all biomolecules on earth (proteins, sugar, amino acids, RNA and DNA), which indicates that it could have arisen from the slight imbalance from the room, which supports the theory that life on earth is an extraterrestrial origin.
Chances of life
A look at the spiral galaxy, which resembles black clouds that swirl in a blue center. | Credit: ESA/Webb, NASA & CSA, J. Lee and the Phangs JWST team., CC BY-NC-ND
The slight imbalance observed in many organic molecules could be an indicator that life on earth comes through the submission of organic molecules through extraterrestrial lifespan. We could definitely be descendants of life that come elsewhere.
The Drake equationDeveloped by astronomers Frank Drake in 1961, offers a framework for the estimate of the number of recognizable civilizations in our galaxy.
This equation contains factors such as the starry rate, the fraction of stars with planets and calculates the fraction of these planets, on which intelligent life can occur. An optimistic estimate that this formula using this formula 12,500 intelligent extraterrestrial civilizations Could exist on a milky way alone.
The main argument for extraterrestrial life remains probabilistically: consideration The sheer number of stars and planetsIt seems very unlikely that life would not have arisen elsewhere.
The probability that humanity is the only technological civilization in the observable universe One of 10 billion trillions. In addition, the likelihood that civilization develops on a single habitable planet is better than one of 60 billion.
With an estimated 200 billion trillion stars in the observable universe, the existence of other technological species is most likely and possibly even in our milky way.
