Home / Science / The alien rain is surprisingly like rain on Earth.

The alien rain is surprisingly like rain on Earth.


image: The infographic compares the projected size of raindrops on different planets.Note that Titan and Mars are currently too cold for raindrops in liquid water. over

Credit: Image credit: AGU

WASHINGTON – Raindrops on other planets and moons are similar in size to the size of raindrops on Earth, although they have different chemical compositions and fall through vastly different atmospheres. The results suggest that raindrops falling from clouds are surprisingly similar in different planetary conditions, helping scientists better understand other worlds̵

7; climates and sedimentation cycles.

Raindrops on Earth are made from water, but other worlds in our solar system precipitate from something more anomalous. On Venus, it rains sulfuric acid. On Jupiter, rain, helium and hail, light ammonia, on Mars, snow, carbon dioxide or dry ice. On Saturn’s moon Titan, rain, methane or liquefied natural gas. And on Neptune, scientists suspect that rain will release pure carbon in the form of diamonds. Even iron or quartz rain on some planets is fine if conditions are right.

A new study into the physics of the working of liquid droplets as they fall from the clouds has found that only aerosols in the clouds within a finite size range – between a radius of about a tenth of a millimeter to several millimeters can reach the ground. The surface of the rocky planets can be precipitation. This is a relatively narrow range, as raindrops increase approximately a million times during the formation inside the clouds.

The results also show the maximum sizes of liquid droplets that fall due to rain are similar in different planetary conditions. Droplets of different types of liquids produce approximately half to six times the size of rain on Earth, depending on the strength of the Earth’s gravitational pull. (The stronger the gravity of the rain, the smaller the raindrops) Find an infographic here for comparing the size of raindrops on Earth, Mars, Jupiter, Saturn and Titan.

Kaitlyn Loftus, a planetary scientist at Harvard University and lead author of the new study in AGU’s Journal of Geophysical Research: PlanetsIt publishes research on the formation and evolution of planets, moons and objects in our solar system and beyond.

Rain on another world

In the new study, Loftus and colleagues Robin Wordsworth used mathematical and physics principles to model how liquid water droplets fall through the planet’s atmosphere. They wanted to determine the possible size range for droplets falling from the cloud to the planet’s surface. Raindrops that are too big will break down into smaller ones, while raindrops that are too small will evaporate before they hit the ground.

First, they determined the possible magnitude ranges for water raindrops on rocky planets such as Earth and Mars, based on atmospheric conditions such as temperature, air pressure, relative humidity, cloud-to-ground distance, and planetary gravitational strength.

They found that raindrops with a radius of about a tenthth of a millimeter smaller than they evaporate before they reach the surface, and raindrops that are several millimeters larger than the radius burst into tiny droplets as they fall.

They then looked at how raindrops in the water could fall on larger planets such as Jupiter and Saturn, with vastly different atmospheres. When comparing modern worlds, ancient Mars, and larger planets, they found that raindrops similarly move water through the air, although what makes up the “air” varies among planets.

Even though different liquids make up raindrops But these alien raindrops are no different from familiar water raindrops, according to the researchers’ calculations. For example, the largest methane raindrops on Titan are about twice the size of the rain on Earth.Loftus is not sure why the maximum rainfall is consistent. But she wondered how it might be because the surface tension of the droplets has to do with their density.

The discovery will help scientists better simulate conditions on other planets because precipitation is a key component in the planet’s climate and nutrient cycles, Loftus said, said Tristan Guillot, a planetary scientist at Observatoire de la Côte d’Azur. In Nice, France, modeling what rain might look like, a new study.

“Now there are such instruments [the James Webb Space Telescope]With the release of this soon, we will have the ability to detect the spectra of exoplanet atmospheres, including those that are much colder than we can characterize, in which clouds and precipitation will occur, ”Guiyote said. “So the tools of this kind developed are very useful and important in interpreting those spectrums.”


AGU (http: // www.ah KuorgSupport 130,000 enthusiasts around the world in Earth and Space Science. Through a broad and comprehensive collaboration, we develop science, discovery and problem solving that accelerates knowledge and create solutions that are ethical, impartial and respectful of communities and values. Our programs include serving as an academic publisher, hosting virtual and one-on-one events and providing professional support. We live our values ​​in everything we do, such as the zero-energy building in Washington, D.C. and our Center for Ethics and Equality, which foster a diverse and inclusive geoscience community to ensure that Responsible practices

Notes for journalists

The study will be free for 30 days.Download a PDF copy of the paper here. Neither paper nor this press release is banned.

Download the multimedia included with this model from the AGU newsroom.

Paper name: “The physics of raindrops falling in the atmosphere of a variety of planets.”


  • Kaitlyn Loftus, Harvard University, Cambridge, Massachusetts
  • Robin Dewsworth, Harvard University, Cambridge, Massachusetts

Warning: AAAS and EurekAlert! Is not responsible for the accuracy of any press releases posted to EurekAlert! By sponsoring the institutions or for the use of any information through the EurekAlert system.

Source link