24/7 Space News
Bouncing comets could deliver building blocks for life to exoplanets
illustration only
Bouncing comets could deliver building blocks for life to exoplanets
by Staff Writers
Cambridge UK (SPX) Nov 15, 2023

How did the molecular building blocks for life end up on Earth? One long-standing theory is that they could have been delivered by comets. Now, researchers from the University of Cambridge have shown how comets could deposit similar building blocks to other planets in the galaxy.

In order to deliver organic material, comets need to be travelling relatively slowly - at speeds below 15 kilometres per second. At higher speeds, the essential molecules would not survive - the speed and temperature of impact would cause them to break apart.

The most likely place where comets can travel at the right speed are 'peas in a pod' systems, where a group of planets orbit closely together. In such a system, the comet could essentially be passed or 'bounced' from the orbit of one planet to another, slowing it down.

At slow enough speeds, the comet would crash on a planet's surface, delivering the intact molecules that researchers believe are the precursors for life. The results, reported in the Proceedings of the Royal Society A, suggest that such systems would be promising places to search for life outside our Solar System if cometary delivery is important for the origins of life.

Comets are known to contain a range of the building blocks for life, known as prebiotic molecules. For example, samples from the Ryugu asteroid, analysed in 2022, showed that it carried intact amino acids and vitamin B3. Comets also contain large amounts of hydrogen cyanide (HCN), another important prebiotic molecule. The strong carbon-nitrogen bonds of HCN make it more durable to high temperatures, meaning it could potentially survive atmospheric entry and remain intact.

"We're learning more about the atmospheres of exoplanets all the time, so we wanted to see if there are planets where complex molecules could also be delivered by comets," said first author Richard Anslow from Cambridge's Institute of Astronomy. "It's possible that the molecules that led to life on Earth came from comets, so the same could be true for planets elsewhere in the galaxy."

The researchers do not claim that comets are necessary to the origin of life on Earth or any other planet, but instead they wanted to place some limits on the types of planets where complex molecules, such as HCN, could be successfully delivered by comets.

Most of the comets in our Solar System sit beyond the orbit of Neptune, in what is known as the Kuiper Belt. When comets or other Kuiper Belt objects (KBOs) collide, they can be pushed by Neptune's gravity toward the Sun, eventually getting pulled in by Jupiter's gravity. Some of these comets make their way past the Asteroid Belt and into the inner Solar System.

"We wanted to test our theories on planets that are similar to our own, as Earth is currently our only example of a planet that supports life," said Anslow. "What kinds of comets, travelling at what kinds of speed, could deliver intact prebiotic molecules?"

Using a variety of mathematical modelling techniques, the researchers determined that it is possible for comets to deliver the precursor molecules for life, but only in certain scenarios. For planets orbiting a star similar to our own Sun, the planet needs to be low mass and it is helpful for the planet to be in close orbit to other planets in the system. The researchers found that nearby planets on close orbits are much more important for planets around lower-mass stars, where the typical speeds are much higher.

In such a system, a comet could be pulled in by the gravitational pull of one planet, then passed to another planet before impact. If this 'comet-passing' happened enough times, the comet would slow down enough so that some prebiotic molecules could survive atmospheric entry.

"In these tightly-packed systems, each planet has a chance to interact with and trap a comet," said Anslow. "It's possible that this mechanism could be how prebiotic molecules end up on planets."

For planets in orbit around lower-mass stars, such as M-dwarfs, it would be more difficult for complex molecules to be delivered by comets, especially if the planets are loosely packed. Rocky planets in these systems also suffer significantly more high-velocity impacts, potentially posing unique challenges for life on these planets.

The researchers say their results could be useful when determining where to look for life outside the Solar System.

"It's exciting that we can start identifying the type of systems we can use to test different origin scenarios," said Anslow. "It's a different way to look at the great work that's already been done on Earth. What molecular pathways led to the enormous variety of life we see around us? Are there other planets where the same pathways exist? It's an exciting time, being able to combine advances in astronomy and chemistry to study some of the most fundamental questions of all."

The research was supported in part by the Royal Society and the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI). Richard Anslow is a Member of Wolfson College, Cambridge.

Research Report:Can comets deliver prebiotic molecules to rocky exoplanets?

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

Subscribe Free To Our Daily Newsletters

The following news reports may link to other Space Media Network websites.
Yucatan underwater caves host diverse microbial communities
Evanston IL (SPX) Nov 13, 2023
With help from an experienced underwater cave-diving team, Northwestern University researchers have constructed the most complete map to date of the microbial communities living in the submerged labyrinths beneath Mexico's Yucatan Peninsula. Although previous researchers have collected water and microbial samples from the cave entrances and easily accessible sinkholes, the Northwestern-led team reached the deep, dark passageways of unlit waters to better understand what can survive inside this uni ... read more

SpaceX Dragon docks with International Space Station carrying new gear

NSF funds annual solicitation seeking physical science research leveraging the ISS National Lab

GreenOnyx's Wanna Greens Makes Space Debut Aboard SpaceX CRS-29 Mission

Cosmic currents: Preserving water quality for astronauts during space exploration

SpaceX 'Starship' launch postponed until Saturday

Southern Launch to host HyImpulse's Pioneering SR75 launch in South Australia

Hypergolic rocket engine with advanced throttling tested by Sierra Space

SpaceX hopes for second Starship flight test next week

Here Comes the Sun: Perseverance Readies for Solar Conjunction

NASA's Mars Missions Persist Through Solar Conjunction

The Long Wait

A green glow in the Martian night

China's BeiDou and Fengyun Satellites Elevate Global Weather Forecasting Capabilities

New scientific experimental samples from China's space station return to Earth

Shenzhou XVI crew return after 'very cool journey'

Chinese astronauts return to Earth with fruitful experimental results

Amazon's Project Kuiper completes successful tests of broadband connectivity

ESA Embracing Commercial Space Stations with Airbus and Voyager Space Partnership

Spire Global launches innovative constellation management platform

A third pair of SES' O3b mPower satellites launches from Cape Canaveral

ReOrbit's Report Highlights Software-First Satellites as Key Growth Drivers in Space Industry

ILLUMA-T launches to the International Space Station

D-Orbit Welcomes Marubeni Corporation as Lead Investor in Series C Funding

Airbus Introduces "Detumbler" Device to Address Satellite Tumbling in Low Earth Orbit

Extended habitability of exoplanets due to subglacial water

An ammonia trail to exoplanets

Bouncing comets could deliver building blocks for life to exoplanets

Webb detects water vapor, sulfur dioxide and sand clouds in the atmosphere of a nearby exoplanet

Fall into an ice giant's atmosphere

Juno finds Jupiter's winds penetrate in cylindrical layers

Salts and organics observed on Ganymede's surface by June

New jet stream discovered in Jupiter's upper atmosphere

Subscribe Free To Our Daily Newsletters


The content herein, unless otherwise known to be public domain, are Copyright 1995-2023 - 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.