Sunday, August 12, 2018

Scientists discover a 'young Jupiter'

A team of astronomers led by Bruce Macintosh of the University of Standford (USA) has discovered thanks to the Gemini Planet Imager (GPI) instrument, a cutting-edge camera to capture planets, a planet very similar to Jupiter, a "young Jupiter "that weighs twice as much as this one but much less than the exoplanets observed so far directly. Its mass is approximately five times more than Jupiter.

"To detect exoplanets, other telescopes such as Kepler from NASA see its shadow; however, GPI sees its brightness, which is what we refer to as a direct image, "explains Macintosh.

His name is 51 Eridani b and orbits around the 51st Eridani star just 13 astronomical units away from its star, which is about 20 million years old.

Thanks to Gemini Planet Imager and its ability to detect objects that have a density much lower than any of those already discovered, it is possible to locate young planets like this one that still retain the heat derived from their formation stage. Thus, in examining thermal emissions, scientists have discovered that methane is the main component of its atmosphere, as in Jupiter.

In the study they also explain that this exoplanet formed in a similar way to the process that Jupiter experienced in its evolution. The finding has been published in the journal Science.

Monday, August 6, 2018

Jupiter would have ejected a giant planet from the solar system

As if it were a cosmic chess game, a team of astrophysicists from the University of Toronto (USA) has discovered that a close encounter with the planet Jupiter about 4,000 million years ago could have led to the expulsion of another giant planet (the fifth) of our solar system. The study has been published in the journal The Astrophysical Journal.

For years scientists have theorized about the existence of this fifth giant planet next to Jupiter, Saturn, Uranus and Neptune, which could have been expelled by Saturn or by Jupiter as a result of a planetary encounter in which one of them is freed from the gravitational attraction of its star. Now, new evidence suggests that Jupiter was responsible for this event.

To reach this conclusion, the astrophysicists studied the moons of these two gaseous giants as well as their moons generating computer simulations based on the current trajectories of Callisto and Iapetus, satellites in regular orbit around Jupiter and Saturn, respectively. Once the simulations were developed, they proceeded to measure the probabilities that Callisto and Iapetus would have generated their current orbit if their host planets had expelled that hypothetical fifth planet from the solar system, since this event would have considerably modified its original orbi

The results revealed that "Jupiter was able to eject the fifth giant planet, keeping a moon with Callisto's orbit. On the other hand, it would have been very difficult for Saturn to do it because Iapetus would have been excessively unstable, because of the result of an orbit that is difficult to reconcile with its current trajectory, "explains Ryan Cloutier, lead author of the study.

Monday, July 23, 2018

The threat that comes from space

Although we have always thought that if there was danger that something would fall on our heads would be asteroids, a team of astronomers from the University of Buckingham and Armagh Observatory have warned that the real danger comes from a few peculiar objects located in the outer Solar System and that have been observed during the last two decades.

These giant objects are called Centaurs, since they seem to be a mixture of asteroids and comets (like the mythological Centaur half man, half horse), move in unstable trajectories while crossing the orbits of Jupiter, Saturn, Uranus and Neptune. Obviously, the gravitational pulls to which they are subjected by these gaseous giants cause their orbits to be altered and that, from time to time, they enforce the path to Earth.

The Centaurs have a typical size of 50 to 100 km and a single body has more mass than the set of all the asteroids that cross the Earth's orbit discovered to date. According to the calculations made by this team of astronomers, one of these Centaurs goes towards the Earth once every 40,000-100,000 years, although the problem is not that it is going to hit us; It is something much worse. When it is close to the Sun it disintegrates, creating a cloud of dust and solid debris and flooding the inner Solar System with debris that makes the impact of some of them with our planet inevitable.