oumuamua Archives

May 18, 2023May 18, 2023 by Evan Gough

A Few Interstellar Objects Have Probably Been Captured

Artist’s impression of the first interstellar asteroid/comet, "Oumuamua". This unique object was discovered on 19 October 2017 by the Pan-STARRS 1 telescope in Hawaii. Credit: ESO/M. Kornmesser

When Oumuamua travelled through our Solar System back in 2017, people around the world paid attention. It was the first Interstellar Object (ISO) astronomers had ever identified. Then in August 2019, Comet 2I Borisov travelled through our Solar System, becoming the second ISO to cruise through for a visit. Together, the visiting ISOs generated a wave of inquiry and speculation.

There’s bound to be more ISOs than just those two, and a new study says our Solar System has probably captured some of these interstellar visitors, though they don’t stay for long.

August 3, 2022August 3, 2022 by Scott Alan Johnston

An Interstellar Meteor Struck the Earth in 2014, and now Scientists Want to Search for it at the Bottom of the Ocean

Artist's illustration of a meteorite resting on the floor of the ocean.

Back in 2014, an object crashed into the ocean just off the coast of Papua New Guinea. Data collected at the time indicated that the meteorite just might be an interstellar object, and if that’s true, then it’s only the third such object known (after Oumuamua and Borisov), and the first known to exist on Earth. Launching an undersea expedition to find it would be a long shot, but the scientific payoff could be enormous.

September 27, 2021September 27, 2021 by Evan Gough

What Happens to Interstellar Objects Captured by the Solar System?

An artist’s overview of the mission concept for the Comet Interceptor spacecraft. Credit: ESA

Now that we know that interstellar objects (ISOs) visit our Solar System, scientists are keen to understand them better. How could they be captured? If they’re captured, what happens to them? How many of them might be in our Solar System?

One team of researchers is trying to find answers.

August 26, 2021August 26, 2021 by Brian Koberlein

Interstellar Objects Might Outnumber Solar System Objects in the Oort Cloud

Artist’s impression of the interstellar object, `Oumuamua, experiencing outgassing as it leaves our Solar System. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

Our solar system is filled with everything from planets to rocky asteroids to small icy bodies beyond Pluto, but surrounding all of it is a diffuse halo of objects known as the Oort cloud. We haven’t directly observed the Oort cloud, but we’re pretty sure it’s there by observing the distribution of comet in our solar system. They can appear from any direction in the sky rather than just along the common plane of known solar system bodies.

July 28, 2021July 29, 2021 by Matt Williams

A New Plan to Search for Extraterrestrial Artifacts at Earth and Across the Solar System

Swarm of laser-sail spacecraft leaving the solar system. Credit: Adrian Mann

On October 19th, 2017, astronomers made the first-ever detection of an interstellar object (ISO) in our Solar System. This body, named 1I/2017 U1 (‘Oumuamua), was spotted shortly after it flew by Earth on its way to the outer Solar System. Years later, astronomers are still hypothesizing what this object could have been (an interstellar “dust bunny,” hydrogen iceberg, nitrogen icebergs), with Harvard Prof. Abraham Loeb going as far as to suggest that it might have been an extraterrestrial solar sail.

Roughly three years later, interest in extraterrestrial visitors has not subsided, in part because of the release of the Pentagon report on the existence of “Unidentified Aerial Phenomena.” This prompted Loeb and several of his fellow scientists to form the Galileo Project, a multi-national, multi-institutional research team dedicated to bringing the search for Extraterrestrial Technological Civilizations (ETC) into the mainstream.

July 2, 2021July 2, 2021 by Scott Alan Johnston

A Small Satellite With a Solar Sail Could Catch up With an Interstellar Object

When Oumuamua, the first interstellar object ever observed passing through the Solar System, was discovered in 2017, it exhibited some unexpected properties that left astronomers scratching their heads. Its elongated shape, lack of a coma, and the fact that it changed its trajectory were all surprising, leading to several competing theories about its origin: was it a hydrogen iceberg exhibiting outgassing, or maybe an extraterrestrial solar sail (sorry folks, not likely) on a deep-space journey? We may never know the answer, because Oumuamua was moving too fast, and was observed too late, to get a good look.

It may be too late for Oumuamua, but we could be ready for the next strange interstellar visitor if we wanted to. A spacecraft could be designed and built to catch such an object at a moment’s notice. The idea of an interstellar interceptor like this has been floated by various experts, and funding to study such a concept has even been granted through NASA’s Innovative Advanced Concepts (NIAC) program. But how exactly would such an interceptor work?

April 17, 2021April 17, 2021 by Scott Alan Johnston

When Stars Get Too Close to Each Other, They Cast Out Interstellar Comets and Asteroids

In October 2017, humanity caught its first-ever glimpse of an interstellar object – a visitor from beyond our solar system – passing nearby the Sun. We named it Oumuamua, and its unusual properties fascinated and confounded astronomers. Less than two years later, amateur astronomer Gennady Borisov found a second interstellar object: a comet-like body that began to disintegrate as it passed within 2 AU of the Sun (1 AU equals the distance from Earth to the Sun). Where do these interstellar objects come from? How common are they? With a sample size of just two, it’s difficult to make any generalizations just yet. On the other hand, given what we know about star formation, we can begin to make some inferences about the likely origins of these objects, and what we are likely to see of them in the future.

January 17, 2021January 17, 2021 by Matt Williams

According to the Math, it’s Highly Unlikely That an Intelligent Civilization is Located at Alpha Centauri

The Parkes radio telescope at Parkes Observatory in New South Wales, Australia. Astronomers using the telescope detected what appeared to be a radio signal coming from the direction of Proxima Centauri in April and May 2019. Image via Daniel John Reardon/ Wikimedia Commons.

In December of 2020, the world got a bit of a pre-holiday surprise when it was announced that astronomers at the Parkes radio telescope in Australia had detected a “tantalizing” signal coming from Proxima Centauri (the red dwarf companion of the Alpha Centauri system). Afterward, researchers at Breakthrough Listen consulted the data on the signal – Breakthrough Listen Candidate 1 (BLC1) – and noted the same curious features.

However, the scientific community has since announced that the signal is unlikely to be anything other than the result of natural phenomena. This was also the conclusion reached by Amir Siraj and Prof. Abraham Loeb of Harvard University after they conducted a probability assessment on BLC1. Like the vast majority of candidate radio signals discovered to date, this one appears to be just the forces of nature saying hello.

November 7, 2020November 9, 2020 by Matt Williams

Vera Rubin Should be Able to Detect a Couple of Interstellar Objects a Month

The Vera C. Rubin Observatory is under construction at Cerro Pachon, in Chile. This image shows construction progress in late 2019. The VCO should be able to spot interstellar objects like Oumuamua. Image Credit: Wil O'Mullaine/LSST CC BY-SA 4.0, https://en.wikipedia.org/w/index.php?curid=62504391

The Vera C. Rubin Observatory, formerly the Large Synoptic Survey Telescope (LSST), will commence operations sometime next year. Not wanting to let a perfectly good acronym go to waste, its first campaign will be known as the Legacy Survey of Space and Time (LSST). This ten-year survey will study everything from dark matter and dark energy to the formation of the Milky Way, and small objects in our Solar System.

According to a new study by Amir Siraj and Prof. Abraham Loeb of Harvard University, another benefit of this survey will be the discovery of interstellar objects that regularly enter the Solar Systems. These results, when combined with physical characterizations of the objects, will teach us a great deal about the origin and nature of planetary systems (and could even help us spot an alien probe or two!)

August 25, 2020August 26, 2020 by Matt Williams

We Have the Technology to Retrieve a Sample From an Interstellar Object Like Oumuamua

On October 19th, 2017, astronomers were astounded to learn that an interstellar object (named ‘Oumuamua) flew by Earth on its way out of the Solar System. Years later, astronomers are still debating what this object was – a comet fragment, a hydrogen iceberg, or an extraterrestrial solar sail? What’s more, the arrival of 2I/Borisov two years later showed how interstellar objects (ISOs) regularly enter our Solar System (some even stay!)

It’s little wonder then why proposals are in place to design missions that could rendezvous with an interstellar object the next time one passes by. One such mission is Project Lyra, a concept proposed by researchers from the Initiative for Interstellar Studies (i4is). Recently, an international team led from the I4IS drafted a White Paper that was submitted to the 2023-2032 Planetary Science and Astrobiology Decadal Survey.