The question of ‘we are alone in the universe’ is usually patronized by philosophers, but now a team of scientists may have a way to find the answer.
They hope to create a list of the planet that will enable astronomers to know where they can point their telescopes.
Thousands of exoplanet – planets orbiting a star outside our solar system have been discovered since the first meeting in 1992. The search is now moving towards which of those planets might be able to sustain life in the hope of answering the question, ‘Are we alone in the universe?’
The new study by a team at the University of Northwestern, Illinois included an investigation of exoplanets orbiting red dwarf stars to determine the effect of a star’s radiation, and its planet’s rotation rate is on habitat.
The lead author, Howard Chen, said: ‘If we can guess which planets are most likely to host life, then to answer the question of whether we are alone in the universe within our lifetime Can be very close. ‘
They found that the radiation of a star is a ‘deciding factor’ as to whether a planet is habitable or not. Using a combination of 3D climate modeling and chemistry analysis, they found how active a star is and the shape of the planet’s ozone layer also plays a role.
This is because radiation emanating from an active star can cause surface water to evaporate, while thin ozone allows too much radiation to pass through, making planets dangerous for complex surface life.
This allowed them to narrow the list of subsistence planets by removing very active stars and planets with very thin ozone layers.
Mr. Chen said: ‘Instruments, such as the Hubble Space Telescope and the James Webb Space Telescope, have the ability to detect water vapor and ozone on exoplanets. They just need to know where to look. ‘
The study focuses on red dwarf stars, also known as M dwarfs because these are the most common types of stars found in the Milky Way, which make up about 70% of the stars in our galaxy.
Our sun is a yellow dwarf, a type of main-sequence star, which is about 7% of the stars found in the Milky Way. A typical red dwarf is 50 times that of the Sun and only 10 to 20 percent of the size of our star.
For a planet to maintain complex life it needs to be able to retain liquid water. If it is too close to the star then the water will evaporate, if it is too far away the water will freeze and if this happens the surface will not be hot enough to sustain complex life.
The planets in the middle are able to sustain the most complex of lives, an area known as the Goldilocks region followed by the fairy tale Goldilocks and Three Beers where Goldilocks is a porridge too hot, one too cold and one feels right is. ‘.
The team is trying to figure out how close to a planet is to retain liquid water. They are trying to discover the ‘inner edge’ of the habitable zone. “The inner edge of our solar system is between Venus and Earth,” Mr. Chen explained. ‘Venus is not habitable; Is the earth. ‘
The team found that many planets in the habitable zone could not stay long due to the thin ozone layers. Despite the otherwise habitable surface temperature, the ozone layers of these planets allow much ultraviolet radiation to pass through and penetrate the ground. Radiation levels would be hazardous to surface life.
Senior researcher Daniel Horton on the project said: ‘There are a lot of stars and planets, which means a lot of goals. Our study may help to limit the number of places where our telescopes point. ‘
Earlier scientists have used one-dimensional and two-dimensional global climate models to study the Red Dwarf planets, but have not taken chemistry into account, so have not been able to give as true a picture, Mr. Chen says.
‘3D photochemistry plays a big role because it provides heating or cooling, which can affect thermodynamics and perhaps the atmospheric composition of a planetary system.’
The research was conducted in collaboration with researchers from the University of Colorado Boulder, NASA’s Virtual Planet Laboratory, and the Massachusetts Institute of Technology.
Mr. Chen said for most of human history, the question of whether or not life exists elsewhere is only within the philosophical field. ‘It is only in recent years that we have modeling tools and observational techniques to address this question.’