The Milky Way may be teeming with planets with oceans and continents like here on earth

Astronomers have long looked at the vast universe in the hope that they will discover alien civilizations. But for a planet to have life, liquid water must be present. The probability of that scenario seems impossible to calculate, because it was the assumption that planets like Earth got their water by chance when a large iron steroid hit the planet.

Now, researchers from the GLOBE Institute at the University of Copenhagen have published a striking study that suggests that there may be water during the formation of a planet. According to the calculations of the study, this applies to Earth, Venus and Mars.

“All our data indicate that water was part of the Earth’s building blocks from the beginning. And because the water molecule occurs frequently, there is a reasonable probability that it applies to all planets in the Milky Way. The decisive point is water present. is, is the distance of the planet from its star, “says Professor Anders Johansen of the Center for Star and Planet Formation, who led the study, which is published in the journal. Scientific progress.

Anders Johansen and his team calculated using a computer model how fast planets are formed and from which building blocks. The study indicates that it is dust particles of ice and carbon millimeters in size – known to orbit all young stars in the Milky Way – that increased 4.5 billion years ago in the formation of what would later become Earth.

“Up to the point where the earth grew to one percent of its current mass, our planet grew by trapping masses of rocks filled with ice and carbon. The earth then grew faster and faster until after five million years it became so large. became as we know it today.On the way, the temperature on the surface rose sharply, causing the ice in the pebbles to evaporate on its way down to the surface, so that today only 0.1 percent of the planet consists of water, even though 70 percent of the earth’s surface is covered by water, ‘says Anders Johansen, who ten years ago, together with his research team in Lund, put forward the theory that the new study now confirms.

The theory, called ‘pebble growth’, is that planets are formed by pebbles that clump together, and that the planets then get bigger and bigger.

Anders Johansen explains that the water molecule H₂O is found everywhere in our galaxy, and that theory therefore opens up the possibility that other planets may be formed in the same way as Earth, Mars, and Venus.

“All planets in the Milky Way can be formed by the same building blocks, which means that planets with the same amount of water and carbon as the earth – and therefore potential places where life can be – regularly occur around other stars in our galaxy, provided the temperature is right , ‘he says.

If planets in our galaxy had the same building blocks and the same temperature conditions as the earth, there is also a high chance that they could have about the same amount of water and continents as our planet.

Professor Martin Bizzarro, co-author of the study, says:

“According to our model, all planets get the same amount of water, and this indicates that other planets not only have the same amount of water and oceans, but also the same amount of continents as here on earth. It offers good opportunities for the rise of life,” he says. he.

If, on the other hand, the amount of water on planets is random, the planets may look very different. Some planets would be too dry to develop life, while others would be completely covered by water.

“A planet covered by water would, of course, be good for maritime beings, but provide less than ideal conditions for the formation of civilizations that the universe can observe,” says Anders Johansen.

Anders Johansen and his research team are looking forward to the next generation of space telescopes, which offer much better opportunities to observe exoplanets orbiting a star other than the Sun.

“The new telescopes are powerful. They use spectroscopy, which means that by noting what kind of light from the planets’ orbit around their star is blocked, you can see how much water vapor there is. This can tell us something about the number of oceans on that planet, ”he says.