After ten years of work, a team of astrophysicists has just listed the planetary systems that are most similar to our solar system. In addition to Earth-like planets, the systems listed in their Kepler giant planet search feature at least one gas giant similar in size to Jupiter; In fact, the latter is thought to have greatly influenced the structure of our solar system… and perhaps the emergence of life on Earth.
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Our solar system is the only planetary system where we know life has evolved; This is therefore our only starting example for the search for possible analogues that could host habitable worlds. Compared to the other systems discovered today, it also has supposedly special characteristics: For example, in its interior it contains four small rocky planets (Mercury, Venus, Earth and Mars) and four gas giants (Jupiter, Saturn, Uranus and Neptune). ) in its outer part. And of all these planets, only one, Earth, contains liquid water on its surface, an essential ingredient for the emergence of life as we know it. According to scientists, the current structure of our solar system (the order of planets and their distance from the Sun) was not always the same, and shortly after its formation, numerous planetary migrations took place, which led to the passage of water on the young Earth and the appearance of the first living organisms make possible …
The importance of Jupiter in our solar system
Shortly after the birth of the Sun, our star, over the course of several million years, the planets formed within the protoplanetary disk – a disk of gas and dust that swirls around the young star. According to the most commonly accepted models today, the planets were much more compact then than they are today and were all closer to the Sun. They then dispersed the mutual gravitational influences throughout the solar system, in particular by gradually moving the gas giants away from each other and closer together, towards the orbits that we know for them today. One of the main consequences of these planetary migrations comes from Jupiter, the largest and most massive planet orbiting our sun.
Jupiter’s migration through the solar system would have actually destabilized the orbits of low-mass objects in the outer zone of the solar system. Objects would have been ejected from the solar system, while some of them would have traveled even further away, giving rise to the Kuiper Belt; The remainder would have migrated to the inner reaches of the solar system, part of which would have collided with the terrestrial planets, including Earth, leading to the Great Late Bombardment about 4 billion years ago. The same gravitational destabilizations would also have pushed water-rich ice objects into the inner part of our solar system and inevitably towards Earth.
Jupiter’s presence in its current location continues to bring debris into the inner solar system today. Thus, Jupiter appears to have played a remarkable role in structuring the solar system and even in the emergence of life on Earth. However, although this entire model seems to work well with what we observe today, it is impossible for us to travel back in time to observe these phenomena. With this in mind, a team of scientists from the University of Notre Dame in the United States has compiled a catalog of planetary systems that contain both Earth-like exoplanets and at least one Jupiter-like gas giant.
A catalog of the systems most similar to the solar system?
Their Kepler Giant Planet Search (KGPS) was created using the database collected by the WM Keck Observatory in Hawaii. The authors recorded nearly 3,000 radial velocities of 63 Sun-like stars orbiting 157 known minor planets, ranging in size from Mars to Neptune. Some of them have solid rocky surfaces that could be suitable for life. But gas giants are generally difficult for astronomers to find because some detection methods don’t work for them. The Kepler Space Telescope, whose mission ended in 2018, has been a great tool for scientists looking for small exoplanets orbiting close to their stars. He used the transit method, which measures tiny fluctuations in a star’s brightness to indicate the presence of a planet orbiting it.
However, things are different for gas giants: they are generally much further away from their stars. Jupiter, for example, takes about 12 years to orbit the sun. In addition, unlike planets near their stars, distant planets often have slightly tilted orbits when viewed from Earth, making fluctuations in brightness less significant. To address this problem, the scientists involved in the development of the catalog used the radial velocity method: this method measures the relative speed of stars and their possible variations, which indicate the presence of a planet in orbit. The intensity of these fluctuations provides information about the mass and distance of the exoplanet from its star. However, these fluctuations are often small, even though gas giants have a strong gravitational pull. The scientists therefore had to carry out a large number of measurements for each star they observed, sometimes over several hundred nights for a single star.
Ultimately, the efforts paid off as scientists managed to create the first catalog listing the currently known planetary systems that are most similar to the solar system. They hope that the in-depth study of the identified systems will make it possible to better understand the connection between the presence of gas giants in a planetary system and the architecture of the latter, and perhaps even to know whether the presence of Jupiter in our whether the solar system is responsible for the The origin of life on earth was of essential importance or not.