Interstellar Object Archives

December 4, 2024December 4, 2024 by Evan Gough

Here’s How Interstellar Objects and Rogue Planets Can be Trapped in the Solar System

Illustration of an interstellar object approaching our solar system. Credit: Rubin Observatory/NOIRLab/NSF/AURA/J. daSilva

When Oumuamua traversed our Solar System in 2017 it was the first confirmed Interstellar Object (ISO) to do so. Then in 2019, Comet 2l/Borisov did the same thing. These are the only two confirmed ISOs to visit our Solar System. Many more ISOs must have visited in our Solar System’s long history, and many more will visit in the future. There are obviously more of these objects out there, and the upcoming Vera Rubin Observatory is expected to discover many more.

It’s possible that the Sun could capture an ISO or a rogue planet in the same way that some of the planets have captured moons.

It all comes down to phase space.

November 30, 2024November 30, 2024 by Brian Koberlein

Interstellar Objects Can't Hide From Vera Rubin

Artist impression of the interstellar comet 2I/Borisov as it travels through our solar system. Credit: NRAO/AUI/NSF, S. Dagnello

We have studied the skies for centuries, but we have only found two objects known to come from another star system. The first interstellar object to be confirmed was 1I/2017 U1, more commonly known as ?Oumuamua. It was discovered with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) and stood out because of its large proper motion. Because ?Oumuamua swept through the inner solar system, it was relatively easy to distinguish. The second interstellar object, 2I/Borisov, stood out because it entered the inner solar system from well above the orbital plane. But while we have only discovered two alien visitors so far, astronomers think interstellar objects are common. It’s estimated that several of them visit our solar system each year, and there may be thousands within the orbit of Neptune on any given day. They just don’t stand out, so we don’t notice them. But that could soon change.

March 13, 2024March 13, 2024 by Brian Koberlein

A 790,000 Year-Old Asteroid Impact Could Explain Seafloor Spherules

A 0.4-millimeter diameter iron-rich spherule. Credit: Avi Loeb/The Galileo Project

Our solar system does not exist in isolation. It formed within a stellar nursery along with hundreds of sibling stars, and even today has the occasional interaction with interstellar objects such as Oumuamua and Borisov. So it’s reasonable to presume that some interstellar material has reached Earth. Recently Avi Loeb and his team earned quite a bit of attention with a study arguing that it had found some of this interstellar stuff on the ocean seabed. But a new study finds that the material has a much more local origin.

February 29, 2024February 29, 2024 by Matt Williams

When an Object Like ‘Oumuamua Comes Around Again, We Could be Ready With an Interstellar Object Explorer (IOE)

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

On October 19th, 2017, astronomers with the Pann-STARRS survey observed an Interstellar Object (ISO) passing through our system – 1I/2017 U1 ‘Oumuamua. This was the first time an ISO was detected, confirming that such objects pass through the Solar System regularly, as astronomers predicted decades prior. Just two years later, a second object was detected, the interstellar comet 2I/Borisov. Given ‘Oumuamua’s unusual nature (still a source of controversy) and the information ISOs could reveal about distant star systems, astronomers are keen to get a closer look at future visitors.

For instance, multiple proposals have been made for interceptor spacecraft that could catch up with future ISOs, study them, and even conduct a sample return (like the ESA’s Comet Interceptor). In a new paper by a team from the Southwest Research Institute (SwRI), Alan Stern and his colleagues studied possible concepts and recommended a purpose-built robotic ISO flyby mission called the Interstellar Object Explorer (IOE). They also demonstrate how this mission could be performed on a modest budget with current spaceflight technology.

February 12, 2024February 12, 2024 by Evan Gough

The Vera Rubin’s Keen Eye On Our Solar System Will Inspire Future Missions

View of Rubin Observatory at sunset in December 2023. The 8.4-meter telescope at Rubin Observatory, equipped with the highest-resolution digital camera in the world, will take enormous images of the southern hemisphere sky, covering the entire sky every few nights. Rubin will do this over and over for 10 years, creating a timelapse view of the Universe that’s unlike anything we’ve seen before. What new Solar System exploration missions will of these observations inspire? Image Credit: RubinObs/NSF/AURA/H. Stockebrand

When the interstellar object (ISO) Oumuamua appeared in our Solar System in 2017, it generated a ton of interest. The urge to learn more about it was fierce, but unfortunately, there was no way to really do so. It came and went, and we were left to ponder what it was made of and where it came from. Then, in 2019, the ISO comet Borisov came for a brief visit, and again, we were left to wonder about it.

There’s bound to be more of these ISOs traversing our Solar System. There’s been talk of having missions ready to go to visit one of these interstellar visitors in the future, but for that to happen, we need advance notice of its arrival. Could the Vera Rubin Observatory tell us far enough in advance?

November 13, 2023November 13, 2023 by Brian Koberlein

The Oort Cloud Might be More Active Than We Thought

The paths of hyperbolic-orbit comets. Credit: NAOJ

Every now and then a comet or asteroid comes to our solar system from interstellar space. We have observed two interstellar objects in recent years, Oumuamua in 2017, and Borisov in 2019. One would assume then that in the past at least some interstellar objects have struck Earth. But we’ve never found an interstellar meteorite. A new study argues that this is because the Oort cloud is much more active than we thought.

October 31, 2023November 1, 2023 by Nancy Atkinson

Vera Rubin Observatory Could Find Up to 70 Interstellar Objects a Year

The Vera C. Rubin Observatory is under construction at Cerro Pachon, in Chile. This image shows construction progress in late 2019. The observatory should be able to spot interstellar objects like Oumuamua. Image Credit: Wil O'Mullaine/LSST .

Astronomers have discovered two known interstellar objects (ISO), ‘Oumuamua and 21/Borisov. But there could be thousands of these objects passing through the Solar System at any time. According to a new paper, the upcoming Vera Rubin Telescope will be a fantastic interstellar object hunter, and could possibly find up to 70 objects a year coming from other star systems.

August 13, 2023August 13, 2023 by Brian Koberlein

Vera Rubin Will Find Many More Interstellar Objects

Most of the comets we see in the sky were born in our solar system. They may have formed deep within the Oort cloud, and for some, it is their first visit to the inner solar system, but they are distinctly children of the Sun. We know of only two objects that came from beyond our solar system, Omuamua and Borisov. There are likely other interstellar objects visiting our solar system, we just haven’t found them. But that’s likely to change when Rubin Observatory comes online.

July 28, 2023July 28, 2023 by Matt Williams

If Rogue Planets are Everywhere, How Could We Explore Them?

This artist’s impression shows an example of a rogue planet with the Rho Ophiuchi cloud complex visible in the background. Rogue planets have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Image Credit: ESO/M. Kornmesser/S. Guisard

At one time, astronomers believed that the planets formed in their current orbits, which remained stable over time. But more recent observations, theory, and calculations have shown that planetary systems are subject to shake-ups and change. Periodically, planets are kicked out of their star systems to become “rogue planets,” bodies that are no longer gravitationally bound to any star and are adrift in the interstellar medium (ISM). Some of these planets may be gas giants with tightly bound icy moons orbiting them, which they could bring with them into the ISM.

Like Jupiter, Saturn, Uranus, and Neptune, these satellites could have warm water interiors that might support life. Other research has indicated that rocky planets with plenty of water on their surfaces could also support life through a combination of geological activity and the decay of radionuclides. According to a recent paper by an international team of astronomers, there could be hundreds of rogue planets in our cosmic neighborhood. Based on their first-ever feasibility analysis, they also indicate that deep space missions could explore these unbound objects more easily than planets still bound to their stars.

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.