Another interstellar object identified entering the solar system
Astronomers think they have identified another interstellar object that is now entering the solar system.
The dim space rock is currently at about magnitude 18.8. Our new visitor, A11pl3Z, will get its closest to the sun – at about 2 astronomical units (AU), or twice as far as Earth is from the sun – in October. As it reaches perihelion – its closest point to the sun – it should be moving at about 68 km/s relative to the sun, or at about 152,000 miles per hour.
The object’s calculated path through the solar system, shown by the blue line in the graphic to the right, as well as the object’s high speed, are why the astronomers think it is interstellar in origin. Both facts suggest it is coming from beyond the Oort cloud.
This is the third such object discovered, after Oumuamua (whose nature remains somewhat unknown), followed by Comet 21/Borisov.
UPDATE: The object has now been renamed 3I/Atlas. The “3I” indicates it is the third interstellar object discovered, and “Atlas” refers to the discovering telescope survey.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Astronomers think they have identified another interstellar object that is now entering the solar system.
The dim space rock is currently at about magnitude 18.8. Our new visitor, A11pl3Z, will get its closest to the sun – at about 2 astronomical units (AU), or twice as far as Earth is from the sun – in October. As it reaches perihelion – its closest point to the sun – it should be moving at about 68 km/s relative to the sun, or at about 152,000 miles per hour.
The object’s calculated path through the solar system, shown by the blue line in the graphic to the right, as well as the object’s high speed, are why the astronomers think it is interstellar in origin. Both facts suggest it is coming from beyond the Oort cloud.
This is the third such object discovered, after Oumuamua (whose nature remains somewhat unknown), followed by Comet 21/Borisov.
UPDATE: The object has now been renamed 3I/Atlas. The “3I” indicates it is the third interstellar object discovered, and “Atlas” refers to the discovering telescope survey.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Borisov was boring.
Any spacecraft near its path? It looks to get near Mars’s orbit
Jeff,
According to Phys.org: “A11pl3Z passes just 0.2 AU from Mars on October 3rd, and assets including the Mars Reconnaissance Orbiter may be able to nab it as an +11th magnitude object” https://phys.org/news/2025-07-inbound-astronomers-interstellar.html
I wondered if we had enough time to build a probe, but could we intercept it? I saw the speed and wondered if we could match it?
I see that the Parker Solar Probe moving fastest was 394,736 miles per hour (635,266 kilometers per hour for Lee). That was using a lot of gravity assists from Venus and the Sun over six years.
Pity we don’t just have generic probes in clean rooms waiting to be launched out on short notice when this sort of thing happens.
Agreed.
Now it’s outbound leg–any assets out that way?
Maybe Lucy or other probes are nearby.
Wow! If this keeps up, we are going to need a category like Cool Image Time. A “cool” interstellar traveler category.
I have thought that the New Horizons team should look at this or comets flung out from the Sun as potential targets.
What NH has plenty of is lead time.
You aren’t going to catch this thing from behind, but maybe you could angle in assets that lie ahead, especially if on the chopping block.
Probes currently en route to asteroids or Jupiter could be sacrificed–they can always be replaced later.
We could crash a lander onto the front of something like this and use it to carry the probe out of the solar system.
But that would mean having a few ready at all times. Maybe even in a solar orbit, clockwise and counter clockwise,to keep a high speed probe ready.
Oumuamua is still the oldest of the bunch–I want Lyra for that just due to anomalous acceleration.
This is probably more like Borisov were I to hazard a guess. Conventional.
I’d say the most important thing about this new interstellar interloper is that it pretty well establishes that these things enter our solar system on a fairly frequent basis – seemingly every year or two. Certainly often enough that we should be making arrangements to catch up to and pace one or more of these things. Given their apparent frequency we don’t need to be in any foaming great hurry to get such a project underway, but once we do, we won’t have to wait very long for a suitable target to wander through either.
Looks like it has been renamed it “3I/ATLAS” by the Minor Planet Center, a sub-group of the evil imperialist IAU. I still have not forgiven or forgotten the demotion of Pluto by the IAU.
Jay: I have updated this post, adding an explanation for the new name at the bottom.
To Mr. Eagleson
Knowing the Great Galactic Ghoul’s other name is Murphy, as soon as Comet Interceptor is launched…we’d never see another interstellar object until the spacecraft quit working….