Category: Solar system

callisto galilean moon

All about Callisto (Jupiter’s moon)

The essentials about Callisto (Jupiter’s moon) Diameter: 4,820 km The fourth of the Galilean moons of Jupiter is Callisto. Since it is located further from Jupiter than the other Galilean moons, it does not has to deal with tidal forces. However, it is possible that Callisto has a liquid water subsurface, but this remains to…
Read more

ganymede moon

All about Ganymede (Jupiter’s moon)

The essentials about Ganymede (Jupiter’s moon) Diameter: 5,262 km Ganymede orbits Jupiter in about 7 days. It is the largest moon in the solar system. It is the third of Jupiter’s main moons and, given its distance from the planet, it has an orbital resonance ratio of 1:2:4 with two of the other satellites of…
Read more


Pluto: NASA plans to send an orbiter

– News of November 5, 2019 – Pluto was explored four years ago by the American space probe New Horizons. This speed meeting allowed to make some beautiful photos that generated many questions. Pluto’s surface seems much more active than previously thought, which makes some people think that the dwarf planet could even have an…
Read more


On Enceladus, organic compounds necessary for life

– News of October 8, 2019 – Between 2004 and 2017, the American spacecraft Cassini studied for the first time the Saturnian system from orbit. This prolonged mission made it possible to place a lander on Titan, to measure the rotation of Saturn or to show the amazing features of a tiny moon, Enceladus. With…
Read more

planet venus

All about Venus and news

A new simulation suggests that Venus has had favorable conditions for life during a long time – News of September 24, 2019 – Venus, our closest neighbor, is often referred to as the twin sister of the Earth. Venus has a diameter and mass very close to those of our planet, but there is not…
Read more


All about the sun and news

The essentials about the sun Beside the sun, the planets and moons of the solar system seem insignificant. The sun accounts for 99.86% of the mass of the solar system. It consists mainly of hydrogen and helium that has been continuously fusing for 4.5 billion years. The size of the sun will change a lot.…
Read more


All about Earth and news

The essential about Earth Earth is probably the jewel of the solar system. Endowed with incredible diversity, it is remarkable in many ways. Earth is the densest planet in the solar system. Some experts consider it a double planet. Earth is indeed the only rocky planet in the solar system to have a massive satellite.…
Read more

titan saturn moon

Titan (moon of Saturn) : all you need to know and news

How was the thick atmosphere of Titan formed ? – News of July 21, 2019 – Titan is the only moon in the solar system with a thick atmosphere. However, there is still no consensus on the cause of this exception. The large quantities of nitrogen found there could be brought in the form of…
Read more

planet mars

Planet Mars : all you need to know and news

The Curiosity rover detects a powerful methane peak on the planet Mars – News of June 25, 2019 – We often talk about methane detection on the planet Mars. On Earth, methane is a gas associated with life. In the atmosphere of the planet Mars, it is easily broken by the ultraviolet radiation of the…
Read more

europa moon

All about Europa (Jupiter’s moon) and news

The study of the salinity of Europa’s oceans could tell us if life is possible – News of June 18, 2019 – In the late 1990s, the Galileo mission taught us that Europa, one of Jupiter‘s largest moon, is probably home to an ocean of liquid water under its ice crust. Its magnetic field, its…
Read more


Earth MOOCs (free online courses)

These courses are free if you only want to read the content of the course and to watch the videos. You will have to pay a few dollars if you want to access all of the course, including rating homework, and to have an official certificate to print or to share (on LinkedIn for example).…
Read more


Triton, Neptune’s moon : all you need to know and news

Triton’s geysers will be targeted by the Trident mission or other missions – News of May 12, 2019 – Thirty years ago, the Voyager 2 space probe made the unique flyby of Neptune and Triton. The trajectory of the space probe was studied to fly only 40 000 kilometers height above the largest moon in…
Read more


All about the Moon and news

The collision of the Earth with another planet would have created the Moon – News of March 24, 2019 The story of the creation of the Moon is still the subject of intense debate. The scenario of a giant impact is only one hypothesis among others. This hypothesis was formulated in the mid-2000s. We imagine…
Read more

planet x

All about planet X / planet 9 and news

The observation of another planetary system could explain the orbit of a planet X – News of March 12, 2019 – FarFarOut is part of a class of objects named extreme transneptunians objects. Other objects in this category all have a very eccentric orbit. This is why some researchers believe that a massive object has…
Read more


All about the planet Neptune and news

A new moon of Neptune has just been discovered – News of February 24, 2019 – A new moon of Neptune has been known since 2013, but sometimes it takes time to formalize a discovery. It was named called Hippocamp. This moon is very small, so it looks like an asteroid. However, it could teach…
Read more

Charon moon of Pluto

Charon, Pluto’s moon : all you have to know and news

An underground ocean would be responsible for the large fractures visible on Charon – News of February 19, 2019 – Charon, Pluto’s moon, was photographed by the spacecraft New Horizons. Charon has a diameter of 1200 km, which makes it a huge moon compared to its planet. Its icy surface is lacerated with faults, mountains…
Read more


All about Uranus and news

Simulations fail to fully explain the inclination of Uranus – News of February 3, 2019 – The axis of rotation of Uranus is quite unique in the solar system. This is most likely the result of a collision very early in the planet’s history, or several collisions. But it is difficult to explain that not…
Read more

dwarf planets

All about dwarf planets and news

The solar system could contain 200 dwarf planets – News of January 27, 2019 – The differentiation between planets and dwarf planets is very recent. Until the mid-2000s, schoolchildren learned that Pluto was the ninth planet in the solar system. This changed with the discovery of many Pluto-like bodies in the Kuiper belt. With the…
Read more

io jupiter moon

All about Io (moon of Jupiter) and news

Io would have more than 400 active volcanoes on its surface – News of January 7, 2019 – Currently in orbit around Jupiter, the Juno space probe took a picture of Io, which highlights a volcanic plume on this moon of Jupiter. This photo reminds how Io is a unique and violent world. Of the…
Read more


All about the planet Saturn and news

The rings of Saturn could disappear – News of December 23, 2018 – The rings of Saturn are superb but we are more and more certain that they are only temporary. They could have disappeared in a few hundred million years. A new study published December 17, 2018 describes how the inner part of the…
Read more


All about Ceres and news

The dwarf planet Ceres could shelter life Ceres is a dwarf planet almost 1000 km in diameter and its density is relatively low. We assumed that Ceres was relatively rich in water, and the space probe Dawn confirmed it during its flights over Ceres from 2015, with its spectrometers. The discovery of ammonia reinforces the…
Read more


All about Vesta and news

6% of meteorites on Earth would come from Vesta In the early 2010s, the data collected by the three scientific instruments embarked on the Dawn space probe revealed the complexity of Vesta, a celestial body that could be classified between an asteroid and a planet. Like a planet, the structure of Vesta is differentiated, because…
Read more


All about Jupiter and news

Astronomers discover 12 new moons in orbit of Jupiter – News of July 24, 2018 – We may think that if we try to discover planets in other systems, it is because we found all that there was to find in the solar system. However, it is a misconception : the objects of the solar…
Read more


All about the planet Mercury and news

Mercury would house more water than expected – News of September 26, 2017 – When we think of Mercury, the planet closest to the sun, we imagine a dry and desolate hell. The surprise was great when, in 2012, the Messenger space probe detected ice water at the pole of Mercury. It is currently estimated…
Read more