The harsh youth of the Sun

One of the hottest topics in the 27th joint study of the International Astronomical Society (IAU) in Rio de Janeiro, Brazil includes studying astronomical conditions suitable for the development and survival of primitive life.

The new study shows that compared to 'middle-aged' stars like the Sun, newly formed stars spin faster and produce stronger magnetic fields, which in turn lead to X-rays, ultraviolet rays and parts. more powerful carriers - all these factors can devastate newly formed atmospheres and greatly affect the development of life forms.

The key question for today's natural science is whether life is rare in the universe. By focusing on multidisciplinary experts, from biology, geography, physics and astronomy, researchers are exploring different aspects of this big question, especially how the conditions around Different types of stars in the early stages of development can help or hinder the emergence of life in the solar system. Some of the pioneering scientists in this form of research have just finished the IAU Symposium 264 on 'Changing the sun and stars - impacts on Earth and planets'.

The sun is terrifying - an extremely hot sphere weighs 300,000 times the Earth, radiating huge amounts of energy while firing a million-kilometer hot plasma into space. Very large radiation from this giant star is dangerous when near it, but for the planet like Earth, orbiting the Sun at a safe distance and receiving much more "pleasant" radiation, it is provide a stable source of energy needed to sustain life. The Sun is now calmer and at the middle age, about 4.5 billion years old.

Edward Guinan, professor of astronomy and astrophysics at Villanova University, USA, and the 'Sun by Time' project team studied stars similar to the Sun at an early or late stage. in its life cycle. These "Suns" allow scientists to look through the time window to see the extreme conditions in the early or future of the solar system, as well as the planetary systems around other stars. These studies can lead to new insights into the origin of life on Earth, while revealing the possibility of life somewhere in the universe. This study shows that the Sun is about 10 times faster at the beginning (more than 4 billion years ago) today, creating a stronger and more energetic magnetic field. This also means that the young Sun emitted X-rays and ultraviolet radiation hundreds of times stronger than today.

A research team led by Jean-Mathias Grießmeier of ASTRON in the Netherlands explores another form of magnetic fields - located around planets. They found that the presence of planetary magnetic fields plays an important role in determining the potential of life on planets because this magnetic field can protect from the effects of molecular storms when it is okay. liberated from its aura and the fierce attack of the windy part. Grießmeier said: 'Planetary magnetic fields are important for two reasons: they protect the planet from the flow of molecules carrying electricity, thus preventing the planet's atmosphere from being blown away, while playing the role. games like shields for large cosmic rays. The lack of an internal magnetic field could be the reason why Mars doesn't have an atmosphere today. '

Stars similar to the Sun allow scientists to look through the window of time to see the extreme conditions in the early or future of the solar system, as well as the planetary systems around other stars. . These studies can lead to new insights into the origin of life on Earth, while revealing the possibility of life somewhere in the universe. This study shows that the Sun is about 10 times faster at the beginning (more than 4 billion years ago) today, creating a stronger and more energetic magnetic field. This also means that the young Sun emitted X-rays and ultraviolet radiation hundreds of times stronger than today. (Photo: IAU / E. Guinan)

Guinan explains a new perception in research: 'The Sun does not seem to be a perfect star for a system where life appears. Although it is difficult to argue with the 'success' of the Sun so far, because the solar system is still the only place where life is known, our research indicates that the star is ideal to can support planet life in tens of billions of years could be a orange 'dwarf' star that is smaller and burns more slowly, and is longer than the Sun - about 20-40 billion years. These stars, known as K stars, are very stable with a habitable area and are in a position for 10 billion years. The number of such stars is 10 times that of the Sun, and many of them provide a suitable environment for life for a very long time. '

He continued: 'In terms of speculative nature, we also found indications that planets like Earth are not necessarily the best place for life. Planets 2 to 3 times the mass of Earth with greater gravity can hold the atmosphere in a better way. They may have a larger liquid iron core, thereby creating a stronger magnetic field that protects the planet from cosmic rays. In addition, a larger planet will cool slower and retain its magnetic protection. This type of planet is more suitable for life, but you cannot argue with 'success' in practice'.

Manfred Cuntz, professor of physics at the University of Texas, Arlington, USA, and his collaborators examined the harmful effects and benefits of ultraviolet rays from stars on DNA molecules. This allowed them to study the impact on extraterrestrial carbon-based life forms in habitable areas around other stars. Cuntz said: 'The most significant damage associated with ultraviolet rays comes from UV-C, which is produced in large quantities in the photoluminescent books of F-form stars that are hotter and farther, in chromatography, of stars in orange K and M in red. The Sun is a yellow G-shaped star in the middle. Ultraviolet rays and cosmic rays around a star can 'choose' life forms that can be formed from it '

Rocco Mancinelli, an extraterrestrial biologist from the American Institute for Extraterrestrial Life (SETI), says when life appeared on Earth at least 3.5 billion years ago, it suffered contains intense ultraviolet radiation for 1 billion years before oxygen is released by these life forms forming protective ozone layer. Mancinelli studied DNA to delve into some of the ultraviolet protection strategies that evolved in early life forms and still exist in a recognizable form today. Because any life in other planetary systems suffers from radiation from their star, these methods, which protect the organism from ultraviolet damage, take on the role of external modeling. Earth. Mancielli said: ' We also see ultraviolet radiation as a form of choice. Three areas of life today have similar UV protection strategies, such as DNA repair mechanisms, and water or rock hiding.

Scientists agree that we do not yet know about the popularity or rarity of life in the universe, but Guinan concludes: 'The possible life stage on Earth is nearing its end - according to the space. In ½ to 1 billion years, the Sun will become too bright and too hot for water to exist in liquid form on Earth. '