. 24/7 Space News .
Surprise finding suggests 'water worlds' are more common than we thought
by Staff Writers
Chicago IL (SPX) Sep 09, 2022

It may be tempting to imagine these planets like something out of Kevin Costner's Waterworld: entirely covered in deep oceans. However, these planets are so close to their suns that any water on the surface would exist in a supercritical gaseous phase, which would enlarge their radius. "But we don't see that in the samples," explained Luque. "That suggests the water is not in the form of surface ocean."

Water is the one thing all life on Earth needs, and the cycle of rain to river to ocean to rain is an essential part of what keeps our planet's climate stable and hospitable. When scientists talk about where to search for signs of life throughout the galaxy, planets with water are always at the top of the list.

A new study suggests that many more planets may have large amounts of water than previously thought-as much as half water and half rock. The catch? All that water is probably embedded in the rock, rather than flowing as oceans or rivers on the surface.

"It was a surprise to see evidence for so many water worlds orbiting the most common type of star in the galaxy," said Rafael Luque, first author on the new paper and a postdoctoral researcher at the University of Chicago. "It has enormous consequences for the search for habitable planets."

Planetary population patterns
Thanks to better telescope instruments, scientists are finding signs of more and more planets in distant solar systems. A larger sample size helps scientists identify demographic patterns-similar to how looking at the population of an entire town can reveal trends that are hard to see at an individual level.

Luque, along with co-author Enric Palle of the Institute of Astrophysics of the Canary Islands and the University of La Laguna, decided to take a population-level look at a group of planets that are seen around a type of star called an M-dwarf. These stars are the most common stars we see around us in the galaxy, and scientists have catalogued dozens of planets around them so far.

But because stars are so much brighter than their planets, we cannot see the actual planets themselves. Instead, scientists detect faint signs of the planets' effects on their stars-the shadow created when a planet crosses in front of its star, or the tiny tug on a star's motion as a planet orbits. That means many questions remain about what these planets actually look like.

"The two different ways to discover planets each give you different information," said Palle. By catching the shadow created when a planet crosses in front of its star, scientists can find the diameter of the planet. By measuring the tiny gravitational pull that a planet exerts on a star, scientists can find its mass.

By combining the two measurements, scientists can get a sense of the makeup of the planet. Perhaps it's a big-but-airy planet made mostly out of gas like Jupiter, or a small, dense, rocky planet like Earth.

These analyses had been done for individual planets, but much more rarely for the entire known population of such planets in the Milky Way galaxy. As the scientists looked at the numbers-43 planets in all-they saw a surprising picture emerging.

The densities of a large percentage of the planets suggested that they were too light for their size to be made up of pure rock. Instead, these planets are probably something like half rock and half water, or another lighter molecule. Imagine the difference between picking up a bowling ball and a soccer ball: they're roughly the same size, but one is made up of much lighter material.

Searching for water worlds
It may be tempting to imagine these planets like something out of Kevin Costner's Waterworld: entirely covered in deep oceans. However, these planets are so close to their suns that any water on the surface would exist in a supercritical gaseous phase, which would enlarge their radius. "But we don't see that in the samples," explained Luque. "That suggests the water is not in the form of surface ocean."

Instead, the water could exist mixed into the rock or in pockets below the surface. Those conditions would be similar to Jupiter's moon Europa, which is thought to have liquid water underground.

"I was shocked when I saw this analysis-I and a lot of people in the field assumed these were all dry, rocky planets," said UChicago exoplanet scientist Jacob Bean, whose group Luque has joined to conduct further analyses.

The finding matches a theory of exoplanet formation that had fallen out of favor in the past few years, which suggested that many planets form farther out in their solar systems and migrate inward over time. Imagine clumps of rock and ice forming together in the cold conditions far from a star, and then being pulled slowly inward by the star's gravity.

Though the evidence is compelling, Bean said he and the other scientists would still like to see "smoking gun proof" that one of these planets is a water world. That's something the scientists are hoping to do with JWST, NASA's newly launched space telescope that is the successor to Hubble.

Research Report:Density, not radius, separates rocky and water-rich planets orbiting M dwarf stars

Related Links
University of Chicago
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only
SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Webb takes its first exoplanet image
Paris (ESA) Sep 02, 2022
For the first time, astronomers have used the NASA/ESA/CSA James Webb Space Telescope to take a direct image of an exoplanet. The exoplanet is a gas giant, meaning it has no rocky surface and could not be habitable. The image, as seen through four different light filters, shows how Webb's powerful infrared gaze can easily capture worlds beyond our Solar System, pointing the way to future observations that will reveal more information than ever before about exoplanets. The exoplanet in Webb's image ... read more

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

US should end ISS collaboration with Russia

NASA-funded technology helps relieve symptoms of menopause

NASA, Axiom Space to launch second private astronaut mission to ISS in 2023

NASA repairs issue with Voyager 1 space probe

NASA unsure next Moon rocket launch attempt possible this month

Teams continue to review options for next Artemis I launch attempt

Ariane 5 launches EUTELSAT KONNECT VHTS satellite

ISRO demonstrates new technology with Inflatable Aerodynamic Decelerator

Glaciers flowed on ancient Mars, but slowly

Everything is Dust in the Wind

Martian rock-metal composite shows potential of 3D printing on Mars

A vast and mysterious valley system in the southern Martian highlands

Rocket to carry Mengtian space lab module arrives at launch site

Duo undertake 7-hour spacewalk

Chinese scientist advocates int'l cooperation in space science

China's Shenzhou-14 astronauts carry out spacewalk

Scotland's space sector set to become greenest on Earth

SpaceX launches 51 Starlink satellites, orbital transfer vehicle

Europe's tallest ever communications satellite launched

Sidus Space executes multiple launch agreement with SpaceX

Antenna enables advanced satellite communications testing

NASA awards LISA mission laser instrument contract

Game on at Gamescom

Steel sector cracks on Ukraine, energy price spikes

RIT scientists to study molecular makeup of planetary nebulae using radio telescopes

Astronomers show massive stars can steal Jupiter-sized planets

Two new rocky worlds around an ultra-cool star

SPECULOOS discovers a potentially habitable super-Earth

NASA's Juno Mission Reveals Jupiter's Complex Colors

The PI's Perspective: Extending Exploration and Making Distant Discoveries

Uranus to begin reversing path across the night sky on Wednesday

Underwater snow gives clues about Europa's icy shell

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.