Interstellar Object Archives

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

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

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.

December 25, 2022December 25, 2022 by Andy Tomaswick

Lightweight Picogram-Scale Probes Could be the Best way to Explore Other Star Systems

Inspiration for space exploration can come from all corners. One of the most inspiring, or terrifying, sources of inspiration for some in space exploration came from computer science expert John von Neumann, who laid out a framework for self-replicating machines in a series of lectures he gave in 1948. Ever since then, scientists and engineers have been debating the advantages, and the perils, of such a system.

However, while technology has indeed advanced a long way since the 1940s, it still seems like we are still a long way from having a fully functional von Neumann machine. That is unless you turn to biology. Even simple biological systems can perform absolutely mind-blowing feats of chemical synthesis. And there are few people in the world today who know that better than George Church. The geneticist from Harvard has been at the forefront of a revolution in the biological sciences over the last 30 years. Now, he’s published a new paper in Astrobiology musing about how biology could aid in creating a pico-scale system that could potentially explore other star systems at next to no cost.

November 11, 2022November 11, 2022 by Andy Tomaswick

We’ll Inevitably see Another Interstellar Object. Which Ones Make the Best Targets to Visit?

We finally have the technological means to detect interstellar objects. We’ve detected two in the last few years, ‘Oumuamua and 2I/Borisov, and there are undoubtedly more out there. As such, there’s been a lot of interest in developing a mission that could visit one once we detect it. But what would such a mission look like? Now, a draft paper from a team of primarily American scientists has taken a stab at answering that question and moved us one step closer to launching such a mission.