VLT observations of interstellar comet 3I/ATLAS II

46 bikenaga 35 8/28/2025, 6:25:39 PM arxiv.org ↗

Comments (35)

rbanffy · 5h ago
We really need to be able to launch a sample return mission to interstellar objects. There’s much unique chemistry to be uncovered.
reenorap · 7h ago
An article said this is the 3rd interstellar object detected. Are we detecting more interstellar visitors because they are getting more common, or have our techniques improved over the last few years?
synapsomorphy · 7h ago
Entirely the second. When Vera Rubin starts reporting its regular scans this will be made very clear because we'll probably find 10+ interstellar objects per year at minimum.
hnuser123456 · 6h ago
These things are only a mile or two wide and at the distance of Jupiter. They require extremely sensitive and high-resolution telescopes to detect. There are probably many more of them that are smaller and further.
gus_massa · 7h ago
We launched a new telescope, in 2017 IIRC, that can detect them.
aardvark179 · 7h ago
Our techniques have improved.
galacticaactual · 2h ago
So how is it that nickel is present on this thing with zero corresponding iron?
ccgreg · 41m ago
> We report detection of CN emission and also detect numerous Ni I lines while Fe I remains undetected, potentially implying efficiently released gas-phase Ni.

Where does it say there is zero iron? This is an upper bound, not zero.

briffid · 8h ago
So is it a spaceship or not?
rdtsc · 7h ago
Why would do think it would be a spaceship?
lucky_cloud · 7h ago
I doubt they're serious but some wackos thought Oumuamua was an alien probe due to its unusual shape, and since this new interstellar object is arriving shortly after Oumuamua has left it must be the mothership.

I feel like it's more of a meme than a serious thing for most people.

chatmasta · 6h ago
It wasn’t a wacko theory at first. The wackos are the people who still believed it even after evidence emerged to the contrary.
rbanffy · 5h ago
There are many more rocks in our own solar system than there are interstellar spacecraft. Assuming similar proportions elsewhere makes us conclude it’s never aliens.
Bjartr · 4h ago
Heuristcs that almost always work are right up until they're not.

https://www.astralcodexten.com/p/heuristics-that-almost-alwa...

andyjohnson0 · 6h ago
The Ramans do everything in threes.
exe34 · 6h ago
I'm looking forward to the braking!
rbanffy · 5h ago
The books, unfortunately, didn’t stop on the first.
holoduke · 5h ago
I am getting bombarded with yt videos about this object being half the size of the sun passing our system with the planets aligned in a 0.01% chance perfect geometry etc etc. millions of views. It's incredible what people believe these days. Not a grain of skepticism.
rbanffy · 5h ago
Science teachers have failed their students.
ojosilva · 3h ago
I think the number of wacky believers hasn't changed that much. It's just that now the countless outlets and algorithms venting this nonsense have ballooned to galactic proportions! My dad used to buy these 70/80s UFO magazines back in the day and they were just as nutty.
dylan604 · 5h ago
Do all of the views necessarily translate 1:1 to the number of people that believe it? Some people watch just to see what kooky nonsense people are falling for.
iJohnDoe · 52m ago
They are asking if it is or not. They didn’t say they think it’s a spaceship.

In any case, assumptions shouldn’t be made either either way what it might be, which is the reason to gather more data.

rdtsc · 23m ago
Sure but it's also not a pink elephant and not a flower pot. It's none of those things. We have just as much evidence of those objects flying through space as we have of alien spaceships so far. So it's odd asking "So is it a spaceship or not?" just like it's odd asking "so is it a flower pot?".
LeoPanthera · 6h ago
It is never aliens.
rbanffy · 5h ago
Until it is. ;-)
JPLeRouzic · 8h ago
This is a report about the volatile composition of interstellar objects (ISOs) passing through the Solar System.
tiahura · 8h ago
So telescopes can see nickel being spread at .125g/mile from 200M miles away?
dekhn · 6h ago
Yes, in this case the telescope (array) is composed of many elements. The scopes themselves are very sensitive (so they can detect minute amounts of photons) and the combined array gives a much higher resolution (ability to see things that are very small very far away).

astronomy technology has been improving rapidly and the VLT is one of the best implementations for this kind of problem right now.

gus_massa · 7h ago
An easy home experiment is to get a gas flame, like in the stovetop that is blue and sprink a little of table salt. The important part is the sodium that gives the flame a very strong yellow color.

Salts without sodium give other colors. IIRC cooper gives a green color. This is used by firecrackers makers to get nice colors, and also in the chemistry lab to detect the composition of some salts.

After studding this king of stuff for a few centuries, we have a very good idea of how each element changes the color of the flame, or absorbs some colors of the light that pass trough the mist.

beefnugs · 2h ago
I can't wait until RFKjr knows which colored salts to inject into child's brains to read the flame colors of autisms!
JPLeRouzic · 8h ago
I have a 135-year-old book by Camille Flammarion that explains how astronomers were able to analyze the content of stars with spectroscopy.
dylan604 · 8h ago
StableAlkyne · 8h ago
In the same sense that a weather radar can "see" mist dozens of miles away, yes

There is so much more information available in the electromagnetic spectrum than just the narrow range a human eye can see

exe34 · 7h ago
my favourite today was this one: https://www.sciencedirect.com/science/article/abs/pii/S00224...

measuring pressure with line broadening!?!

DoctorOetker · 4h ago
for example, the element Helium (which had been presumed to exist as a missing gap in the Aufbau model, but at the time not yet discovered) was first discovered not on Earth... but in the Sun! Spectroscopy confirmed the predicted spectrum. Once The element was confirmed to exist on the sun, they started looking for it on Earth and eventually found it on Earth as well.