The top indicates that the object has two names (this is common): 3I/ATLAS = C/2025 N1 (ATLAS)
ATLAS was the telescope that made the discovery.
The list of data are individual observations of the object by different telescopes. This observation format has been in use for a long time, but is being phased out. A row is meant to fit on a single punch card...
These observations are then used to calculate orbits, the MPC calculates the orbit as well, but this list of observations is also ingested by JPL and their Horizons service.
Right now it is mostly just a point on the sky, it is difficult to tell if it is active (like a comet) yet. If it is not active, IE: asteroid like, then the current observations put it somewhere between 8-22km in diameter (this depends on the albedo of the surface). From what we know, we would expect it to likely be made up of darker material meaning given that range of diameters it is more likely to be on the larger end. However if it is active, then the dust coming off can make it appear much larger than it is. As it comes in closer to the sun and starts to warm up it may become active (or more active if its already doing stuff).
It will not pass particularly close to any planet. It will be closest to the sun just before Halloween this year at 1.35 au, moving at 68 km/s (earth orbits at 29-30 km/s). It is also retrograde (IE, it is moving in the opposite direction of planetary motion), for an interstellar object this is basically random chance that this is the case.
Link to an orbit viewer: https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=3I&vi...
The next couple of weeks will be interesting for a bunch of people I know.
Source: Working on my PhD in orbital dynamics and formerly wrote the asteroid simulation code used on several NASA missions: https://github.com/dahlend/kete
I linked an orbit viewer above if you want to look.
Is this also random chance or is there a reason why it's so close to the plane of the solar system?
It is probably random chance, however there may be some biases from where they come from on the sky (I know people who work on that, but I don't know much about it).
N=3 does not provide very robust statistics yet, give us another decade or two.
[1] https://en.m.wikipedia.org/wiki/Extremely_Large_Telescope
I did a full proper n-body integration and it is not visually different than this.
If we could steer it to hit one of Mars’s poles, it might do a bit of terraforming for us!
kinetic energy = 1/2 m v**2 = 1/2 * size * density * v**2
= 1/2 *(22000 m)**3 * (5000 kg/m**3) * (90 m/s)**2 / (4.184E15 J/megaton)
= 52,000 megaton
Or 5-ish Tsar Bomba per country on Earth.
Or 3466 Hiroshima nukes.
Or 17 Hiroshima nukes per country.
…
FWiW .. here's mine (or is it?)
One Tsar Bomba ~ 50 megatonne. One Hiroshima bomb ~ 15 kilotonne.
One Tsar Bomba ~ 50,000 / 15 ~ 3,333 Hiroshima bombs.
1,040 x Tsar Bomba ~ 3,466,667 Hiroshima bombs.
Every time I see your username I can’t help but say it in my mind as Defrost Kelly, some kind of frozen Dr. Leonard "Bones" McCoy
Way too slow, it's more like 70km/s (or 90) - seems you left out a k.
(let* ((ρ ([g (cm -3)] 5))
(d ([km] 22))
(m (* ρ (expt d 3)))
(v ([km (s -1)] 90))
(ke (* 1/2 m (expt v 2)))
(kg-tnt ([J (kg -1)] 4.2e6)))
(values (/ ke kg-tnt)
(as [megaton] (/ ke kg-tnt))))
5.133857142857142e19 [KG]
5.133857142857143e10 [MEGATON]Thanks!
Terraform Mars!
A thick enough atmosphere will stop pretty much all the charged particles from the normal solar radiation.
And clearly even our mag field (and Sun's heliosphere) is not enough to shield us from those crazy cosmic rays.
“We'll be saying a big hello to all intelligent lifeforms everywhere and to everyone else out there, the secret is to bang the rocks together, guys.” - The Hitchhikers Guige to the Galaxy, Douglas Adams
If it is an inactive rock, then we will not see it as any more than a point of light during its visit.
The original URL was https://minorplanetcenter.net/mpec/K25/K25N12.html, which I've included in the header.
In there, one estimate of the number of these objects is
Nisc <~ 7.2 × 10−5 AU−3
ordu•6h ago
1. Astronomers became good enough to notice them 2. These rocks are first in an incoming flood of such objects, the Universe decided to destroy humanity.
em3rgent0rdr•5h ago
noduerme•5h ago
"Third cargo chest discovered"
"Maybe they've been sailing by here already for a long time and we just didn't notice."
haiku2077•5h ago
eesmith•4h ago
People have searched off the orbital plane for a long time, if only to find new comets.
This object was found by ATLAS, the Asteroid Terrestrial-impact Last Alert System. The project goal is to identify near-earth asteroids, evaluate the risk they might impact the Earth, and alert others if impact is predicted.
The project started in 2015, two years before ʻOumuamua. It was not made specifically to find interstellar objects transiting the solar system.
dotnet00•5h ago
tigerlily•1h ago
elchananHaas•5h ago
9dev•5h ago
When ʻOumuamua flew past, we should have noticed it was a passive sensor drone. Now it is too late.
shiroiuma•5h ago
belter•4h ago
phatskat•4h ago
lynx97•3h ago
nandomrumber•3h ago
eb0la•4h ago
polytely•33m ago
https://youtu.be/X3N-DjVXh44
so we are probably gonna notice a lot more of them