Water planets are common in our Milky Way Galaxy, study tips | Astronomy, Planning Science

In a study published in the journal Advances in science, a team of European astronauts show that water can be delivered to a terrestrial planet in the form of ‘hairy snow’ in the early stages of the planet ‘s growth.

Artist’s impression of the water world exoplanet. Image credit: Sci-News.com.

“All of our data shows that water was part of the Earth’s building blocks, right from the start,” said Professor Anders Johansen, a researcher at the Center for Star and Planet Creation at the University of Copenhagen and Lund Observatory.

“And because the water molecule is a regular occurrence, there is a reasonable probability that it will apply to all planets in the Milky Way.”

“The point is that melting water is present at the distance of the planet from its star.”

Using a computer model, Professor Johansen and colleagues described how fast planets are created, and where building blocks come from.

Their findings show that, 4.5 billion years ago, ice and carbon particles of millimeter size were accumulating in the formation of what became Earth.

“Up to the point where the Earth grew to 1% of its current mass, our planet grew by capturing masses of rocks full of ice and carbon,” said Professor Johansen.

“The Earth then grew faster and faster until, five million years later, it became as big as we know it today. ”

“Along the way, the surface temperature suddenly rose, causing the ice in the pebbles to evaporate on the way down to the surface so that, today, it is only 0.1 % of the planet is made up of water, even though 70% of The earth’s surface is covered with water. ”

The team’s stone-collecting theory is that planets are formed by pebbles falling together, and that the planets then grow larger and larger.

“The water molecule is ubiquitous in our Galaxy, so such a theory opens up the possibility that other planets may have been created in the same way as Earth, Mars and Venus, ”Said Professor Johansen.

“All the planets in the Milky Way can be created with the same building blocks, meaning that planets will have the same amount of water and carbon as the Earth – and therefore potential locations. present – appearing frequently around other stars in our Galaxy, as long as they are there the temperature is right. ”

If the planets in our Galaxy had the same building blocks and the same temperature conditions as Earth, there would also be a good chance that they will have about the same amount of water and continents as our planet.

“Our model allows all planets to receive the same amount of water, which shows that other planets may not only have the same amount of water and oceans, but also the same amount of water. of continents as they are here on Earth. It provides great opportunities for life to emerge, ”said Professor Martin Bizzarro, a researcher at the Center for Star and Planet Creation at the University of Copenhagen.

“On the other hand, if it were random how much water was present on planets, the planets might look very different. Some planets would be too dry to improve life, while others would be completely covered with water. ”


Anders Johansen et al. 2021. A model for the formation of rocks for the formation of the terrestrial planets in the Solar System. Advances in science 7 (8): eabc0444; doi: 10.1126 / sciadv.abc0444