By using this site, you agree to the Privacy Policy and Terms of Use.
Accept

Science, Space & Technology

Space Science Digital
Contact
Search
  • Home
  • Environment

    Observe Gemini’s outstanding Messier 35

    February 14, 2023

    Japanese Hakuto-R moon lander reaches slips into lunar orbit

    March 22, 2023

    Webb captures detailed infrared view of Uranus, its moons and dusty rings

    April 7, 2023

    Do galaxy collisions power quasars? And will our Milky Way become a quasar?

    April 26, 2023
  • Space Flight

    Starship debut leading the rocket industry toward full reusability

    March 3, 2023

    A stargazer’s guide to managing light pollution

    March 1, 2023

    Dwarf planet Quaoar has a weirdly big ring of debris encircling it

    February 8, 2023

    SES to complete C-band clearing program with SpaceX dual-satellite launch

    March 16, 2023
  • Cosmology

    Tattered remains of first recorded supernova captured in new image

    March 3, 2023

    Observe hidden gems in the constellation Orion the Hunter

    February 10, 2023

    A Helicopter is Going to Titan. Could an Airplane be Next?

    March 9, 2023

    The First All-Electrical Thruster – the IVO Quantum Drive – is Headed to Space!

    March 16, 2023
  • Latest
  • About Us
Reading: ‘Oumuamua was an outgassing comet, scientists say
Share
Aa
Space Science DigitalSpace Science Digital
  • Environment
  • Space Flight
  • Cosmology
  • Technology
Search
  • Home
  • Categories
    • Environment
    • Technology
    • Cosmology
    • Space Flight
  • More Foxiz
    • Blog Index
    • Forums
    • Complaint
    • Sitemap
Follow US
© 2023 Space Science Digital. All Rights Reserved.
Space Science Digital > Blog > Astronomy > ‘Oumuamua was an outgassing comet, scientists say
Astronomy

‘Oumuamua was an outgassing comet, scientists say

By Aimee Daly March 22, 2023 14 Min Read
Share


Contents
The strange case of ‘OumuamuaAcceleration from outgassingThe source of the outgassingOld research led the wayChasing down ‘OumuamuaIs this the last word on ‘Oumuamua?Future observationsUnlocking mysteries
View larger. | ‘Oumuamua was an interstellar visitor with a strange acceleration when it rounded the sun. Researchers now say that the unusual orbit was due to outgassing on this extrasolar comet. Image via NASA/ ESA and Joseph Olmsted and Frank Summers of STScI.

In 2017, an object later named ‘Oumuamua became known as the first observed interstellar visitor to our solar system. This oblong space rock moved in ways that didn’t fit with what scientists understand about comets or asteroids. Its strange acceleration led to many theories as to what ‘Oumuamua might be, including the idea that it might be an alien spacecraft. On March 22, 2023, researchers at the University of California-Berkeley and Cornell University said they’ve now got a simpler explanation for ‘Oumuamua and its odd behavior. They said the object might be interstellar alright, from another star system. But it could be an ordinary comet, warmed by its passage near our sun, that received an extra push from the outgassing of hydrogen.

Jennifer Bergner of the University of California-Berkeley and Daryl Seligman at Cornell University authored a peer-reviewed study, which published in the journal Nature on March 22, 2023.

The strange case of ‘Oumuamua

‘Oumuamua was the source of many fantastical musings for two reasons: It’s the first-known interstellar visitor, and it’s strange. It was not obviously either a comet or asteroid, and it didn’t move like scientists expected it to.

While it was the first-known interstellar visitor, it’s no longer the only known one. In 2019, astronomers discovered 2I/Borisov, a comet from another solar system that flew past our sun. Borisov acted much more like traditional comets, with a coma and a tail. Additionally, analysis of a meteor that hit Earth in 2014 shows that it, too, was a visitor from another solar system. (Avi Loeb and his group The Galileo Project plan to search for this meteor under the Pacific Ocean in the summer of 2023.)

‘Oumuamua defied classification because of its physical features and motion. It’s shape was somewhere between a pancake and a cigar; it had no coma or tail and was smaller than traditional comets. However, what really made it stand out as unusual was the way it accelerated away from the sun. Many theories have tried to explain this acceleration, but the researchers’ newest theory does the cleanest job.

Acceleration from outgassing

The researchers said the reason ‘Oumuamua experienced a push from the outgassing is because of its small size. All the comets we know of in our solar system have been 0.5 mile to hundreds of miles (1 kilometer to hundreds of kilometers) across, whereas ‘Oumuamua is around 377 feet (115 meters) at its widest. Bergner said:

For a comet several kilometers across, the outgassing would be from a really thin shell relative to the bulk of the object, so both compositionally and in terms of any acceleration, you wouldn’t necessarily expect that to be a detectable effect. But because ‘Oumuamua was so small, we think that it actually produced sufficient force to power this acceleration.

Young woman with long curly hair and glasses smiling with wires behind her.
Jennifer Bergner studied the cause of ‘Oumuamua’s acceleration away from the sun. Image via University of California-Berkeley.

The source of the outgassing

When astronomers observed ‘Oumuamua in 2017, they couldn’t see a coma, outgassed molecules or dust. Plus, their calculations of solar energy on the object couldn’t provide the kick they observed. With the amount of solar energy ‘Oumuamua was getting, the only thing that could provide enough of a non-gravitational kick to match the observed acceleration was a hypervolatile gas. For example, hydrogen (H2). Seligman said:

We had never seen a comet in the solar system that didn’t have a dust coma. So, the non-gravitational acceleration really was weird.

So, if ‘Oumuamua was a comet (even without a visible coma or tail) from interstellar space, is it possible it had a store of hydrogen to outgas and provide the kick that occurred near our sun? Bergner explained:

A comet traveling through the interstellar medium basically is getting cooked by cosmic radiation, forming hydrogen as a result. Our thought was: If this was happening, could you actually trap it in the body, so that when it entered the solar system and it was warmed up, it would outgas that hydrogen? Could that quantitatively produce the force that you need to explain the non-gravitational acceleration?

Old research led the way

Bergner discovered old research dating back to the 1970s that provided the answer. She found studies that said when ice is hit by high-energy particles, such as cosmic rays in interstellar space, it produces an abundance of molecular hydrogen (H2) trapped in the ice. In fact, these cosmic rays are capable of penetrating tens of meters into ice. That means the cosmic rays could convert more than 1/4 of the comet’s water to hydrogen gas.

Past experiments showed that when the sun warms the ice, it changes from an amorphous structure to a crystal structure. This forces bubbles of hydrogen gas out. The gas, ejected in either a beam or fan-shaped spray, would be an ample amount to provide the observed change in ‘Oumuamua’s orbit. Bergner said:

The main takeaway is that ‘Oumuamua is consistent with being a standard interstellar comet that just experienced heavy processing. The models we ran are consistent with what we see in the solar system from comets and asteroids. So, you could essentially start with something that looks like a comet and have this scenario work.

What about ‘Oumuamua’s lack of a coma and tail? Seligman explained:

Even if there was dust in the ice matrix, you’re not sublimating the ice, you’re just rearranging the ice and then letting H2 get released. So, the dust isn’t even going to come out.

Young man with light-colored hair smiling at camera.
Darryl Seligman was one of the authors of the new paper that explains ‘Oumuamua’s strange orbit. Image via Cornell.

Seligman continued:

What’s beautiful about Jenny’s idea is that it’s exactly what should happen to interstellar comets. We had all these stupid ideas, like hydrogen icebergs and other crazy things, and it’s just the most generic explanation.

Chasing down ‘Oumuamua

Seligman was one of the first to suggest that it would be possible to chase down ‘Oumuamua for study. A team called Project Lyra is currently studying the feasibility of launching a spacecraft as early as 2028 to reach ‘Oumuamua by 2047.

EarthSky spoke to Seligman and discussed the idea of exploring ‘Oumuamua or the next interstellar object that comes along. Seligman told EarthSky:

It’s a really exciting thing. We should be finding enough of them that will come close enough to Earth to do a space-based rendezvous.

He said that one neat thing about these objects that come from interstellar space is that they have such high velocities that we wouldn’t need to match orbits with it and crash into it. We’d just have to position a spacecraft or probe in front of it. As Seligman said:

It’s like jumping in front of a speeding car.

Seligman said that one of the things they’d look for is how representative these objects are of interstellar objects. For example, Borisov, which is considered the “more normal” interstellar object, is really not all that similar to comets in our solar system. The chemical composition of Borisov contains much more hypervolatiles than most solar system comets.

Seligman also said that if we could sample the material of an interstellar object or have a probe impact one, it would release the internal material. Inside the object the material is more pristine and less processed, giving us a better idea of the composition of the objects when they were formed in their distant solar systems. We could spectroscopically analyze the material from telescopes on the ground. (Read more about the DART mission that impacted an asteroid.)

Is this the last word on ‘Oumuamua?

Since ‘Oumuamua’s discovery in 2017, scientists have since discovered six other comets without a coma but with similar accelerations. Scientist call these objects dark comets and believe they are common. They don’t believe hydrogen is the responsible source of acceleration in these solar system objects, but their existence teaches us more about these strange types of objects.

One of these dark comets, 1998 KY26, will soon be receiving a visit from Japan’s Hayabusa2 mission. In 2018, the spacecraft explored the asteroid Ryugu.

Seligman talked about how all the pieces are coming together:

Jenny’s definitely right about the entrapped hydrogen. Nobody had thought of that before. Between discovering other dark comets in the solar system and Jenny’s awesome idea, I think it’s got to be correct. Water is the most abundant component of comets in the solar system and likely in extrasolar systems, as well. And if you put a water-rich comet in the Oort cloud or eject it into the interstellar medium, you should get amorphous ice with pockets of H2.

Future observations

Upcoming instruments such as those at the Vera C. Rubin Observatory, slated for operation in 2025, should find more of these objects. The team projects that the Rubin Observatory could detect from one and three interstellar comets like ‘Oumuamua per year, and even more interstellar comets that resemble Borisov.

These interstellar visitors can help us learn even more about solar systems beyond our own. As gravitational interactions eject comets from other suns and send them speeding toward our own, we can get a glimpse of what distant worlds might look like. As Seligman said:

The comets and asteroids in the solar system have arguably taught us more about planet formation than what we’ve learned from the actual planets in the solar system. I think that the interstellar comets could arguably tell us more about extrasolar planets than the extrasolar planets we are trying to get measurements of today.

Unlocking mysteries

Seligman is amazed by the long road it’s taken to come to the solution for ‘Oumuamua’s strange behavior. He’s also awed by how understanding this interstellar visitor helps us learn more about objects such as dark comets in our own solar system. He said:

This thing was only observable for like two weeks but was one of the most scrutinized objects in that period of time. It took five years, going through wild theories, until we got to this idea that is the simplest that actually explains it. It also explains objects in the solar system that we didn’t understand before.

Bottom line: Researchers have solved the mystery of ‘Oumuamua’s strange orbit. Outgassing from hydrogen inside the interstellar comet gave the object the telltale push.

Source: Acceleration of 1I/‘Oumuamua from radiolytically produced H2 in H2O ice

Via University of California-Berkeley

TAGGED: comet, Oumuamua, outgassing, Scientists, space

Sign Up For Daily Newsletter

Be keep up! Get the latest breaking news delivered straight to your inbox.
[mc4wp_form]
By signing up, you agree to our Terms of Use and acknowledge the data practices in our Privacy Policy. You may unsubscribe at any time.
Aimee Daly March 22, 2023
Share this Article
Facebook Twitter Email Copy Link Print
Leave a comment Leave a comment

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

SUBSCRIBE NOW

Subscribe to our newsletter to get our newest articles instantly!

[mc4wp_form]

HOT NEWS

Starship debut leading the rocket industry toward full reusability

Space Flight
March 3, 2023

Is that this black gap jet making stars explode?

Again to Article Listing Greater than twice the anticipated quantity of novae have been discovered…

October 27, 2024

NASA Says Spacecraft Crash Test Successfully Changes Asteroid’s Orbit

CAPE CANAVERAL, Fla. (AP) — A spacecraft that plowed into a small, harmless asteroid millions…

October 11, 2022

World-Saving Spacecraft Passes Test

NASA says its DART spacecraft successfully shifted the path of an asteroid. For us earthlings,…

October 11, 2022

YOU MAY ALSO LIKE

Proposed CASTOR Area Telescope Waits on Authorities

The proposed Canadian led Cosmological Superior Survey Telescope for Optical and uv Analysis, generally referred to by its acronym CASTOR,…

News
October 27, 2024

A trio of elusive Native Group galaxies

IC 10 is a dwarf irregular galaxy that’s a member of our Native Group. Intense star formation right here results…

Astronomy
October 27, 2024

Apollo 8 Earthrise picture anniversary, December 24

The long-lasting “Earthrise” picture of Earth showing over the moon’s horizon as seen from the Apollo 8 spacecraft, taken throughout…

Astronomy
December 23, 2023

12 James Webb House Telescope findings that modified our understanding of the universe in 2023

On Christmas morning two years in the past, astronomers and area followers acquired the present they'd been ready for 30…

News
December 23, 2023
We use our own and third-party cookies to improve our services, personalise your advertising and remember your preferences.
  • Jobs Board
  • About Us
  • Contact Us
  • Privacy Policy
  • Exclusives
  • Learn How
  • Support
  • Solutions
  • Terms And Conditions
  • Editorial Policy
  • Marketing Solutions
  • Industry Intelligence

Follow US: 

Space Science Digital

Welcome to spacescience.digital, A source for the latest news and developments in the exciting field of space science. Our blog covers a wide range of topics, from the latest space missions and discoveries to updates on technology and scientific breakthroughs. We are passionate about sharing the wonders of the universe with our readers and providing them with engaging and informative content. Join us on this fascinating journey as we explore the mysteries of space and the frontiers of human knowledge.

© 2024 Space Science Digital. All Rights Reserved.

Removed from reading list

Undo
Welcome Back!

Sign in to your account

Lost your password?