Posted by gammarator 2 days ago
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
“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is.” ~Douglas Adams
Instead, go out to the ocean on a clear day, and observe how absurdly vast the ocean is. Just ocean, as far as you can see. Look around and realize you’ve gained absolutely nothing in terms of comprehending the vastness of space, to which the difference between your room and the most sweeping views on Earth are just totally insignificant.
https://www.joshworth.com/dev/pixelspace/pixelspace_solarsys...
https://www.youtube.com/watch?v=1AAU_btBN7s
[edit] arrgh. brain spaz forgot to put in the URL
Not if it's at the speed of light, the journey will be instantaneous for the (massless) traveller.
For example, this image from a park in Halle (Germany) shows the inner solar system: https://dubisthalle.de/wp-content/uploads/2023/06/Planetenwe... -- but one has to walk 500 meters to reach Pluto.
The German Wikipedia has quite a long list of planetary trails: https://de.wikipedia.org/wiki/Planetenweg
They compare it to a US football field.
"On this scale, the Sun, by far the largest thing in our solar system, is only a ball about two-thirds of an inch (17 millimeters) in diameter sitting on the goal line — that's about the width of a U.S. dime coin. ...
The inner planets — Mercury, Venus, Earth and Mars — are about the size of grains of sand on a football field scale. They would be dwarfed by a typical flea, which is about 3 millimeters long.
Closest to the goal line is Mercury, just under a yard from the end zone (.8 yards to be specific). ... At this scale, Mercury's diameter would be scarcely as large as the point of a needle.
Venus is next. It is 1.4 yards from the end zone. ...
On to Earth, sitting pretty on the 2-yard line. ...
Mars is on the three-yard line of our imaginary football field. ...
Jupiter remains pretty close to our end zone on the 10.5-yard line. ...
Saturn is on the field at 19 yards from the goal line. ...
Uranus ... is about 38 yards from our end zone.
Neptune is where things start to get way out. It is 60 yards from our solar goal line on the imaginary football field. ...
Tiny Pluto is much closer to the opposing team's end zone. It's about 79 yards out from the Sun ...
On this scale, our little friend Voyager 1 has left the game and is well out in the stadium parking lot or beyond."
[1] https://www.newyorker.com/magazine/2007/02/12/a-tranquil-sta...
"If life is going to exist in a Universe of this size, then the one thing it cannot afford to have is a sense of proportion." -DNA
Hell, maybe it's only orbiting the galaxy at a leisurely 160 km/s, and from its perspective we're a spinning disc of chaos zipping past it for the first time in a few million years! I don't even know how I would start to analyze its orientation in relation to the galactic center, but I'll be keeping this as my little "headcannon" until proven wrong, that's for sure.
[1] https://www.reddit.com/r/space/comments/1lpw4as/new_interste...
Terraform Mars!
“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
But are you implying that we are somehow more evolved than the monkeys? Both the human and the monkey in the story have evolved for the same amount of time since our last common ancestor.
Would you claim that they all traveled the same distance because they all traveled for the same amount of time?
Evolutionary space is very high dimension, which makes the argument that just projecting onto the (1d) time axis is misleading even stronger.
Which one is more numerous, less prone to natural forcings?
Where I see the model flounder is; the hill provides the fitness context. You implied distance "means" more evolved, but for life it is all about making it to the next round, in your marble game how many of those furthest marbles will ever be found for the next round?
With life big changes are dangerous, you may find yourself improved out of options.
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.
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
(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!
Mauna Loa is about 95,000 km3 in volume says https://www.usgs.gov/volcanoes/mauna-kea/science/geology-and... . Density of TNT is 1.6g/cm3:
95000 km3 * (1000m/km)**3 * 1600 kg/m3 = ~1.5E17 = 150 pt.
Nope, I can't conceive of that much energy.
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.
"specified object was not found"
What do you mean by 'active' here - has a plume?
C/2025 N1
Edit: does this link work?
https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=C%2F2...
For ‘Oumuamua in 2017, some method was used to determine its shape, which is (apparently) remarkably elongated. Is it possible to determine the elongation of the new object?
For example, Earth's orbit around the sun is ~0.0167, Pluto's is 0.248.
This is one of the big reasons I love HN
If it is an inactive rock, then we will not see it as any more than a point of light during its visit.
No matter how infinitesimally small the probability - the universe is infinite, and so it probably will happen.
i3 is much bigger than the Chicxulub asteroid that ended the Cretaceous period (and extinct all non-avian dinosaurs).
An object (depending on consistency) of about 100m is enough to wipe out a city and do enough damage to the environment. Something of 8-20km is in the same category as what wiped out the dinosaurs (10-15km).
No, I can’t really imagine what that means, either.
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
It's a fun idea thought though.
https://upload.wikimedia.org/wikipedia/commons/c/c5/Comparis...
I did a full proper n-body integration and it is not visually different than this.
except that it's going the wrong way :)
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.
so we are probably gonna notice a lot more of them
"Third cargo chest discovered"
"Maybe they've been sailing by here already for a long time and we just didn't notice."
When ʻOumuamua flew past, we should have noticed it was a passive sensor drone. Now it is too late.
We might know this better in the next years, depending on whether there will now be an explosion of dozen and dozens of new interstellar objects discovered, or not. It might be another rush, like with exoplanets and local dwarf-planets.
Benevolent aliens are planting incompetent people in positions of power so that we are perpetually on the verge of self-annihilation. But this is all to save us from the malevolent aliens who would obliterate us if they thought we had any chance of survival.
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.
We genuinely don't any idea how many it will be, so I'm hoping for a lot!
Imagine when we can get real sample material from other solar systems!
In there, one estimate of the number of these objects is
Nisc <~ 7.2 × 10−5 AU−3
Perhaps Oumuamua was the mothership and the solar system is now swarming with cubesats we're not noticing.
Or maybe the size of a sub-atomic particle, as in the sci-fi Novel 'The 3 body problem'.
Time to quit my job at the LHC and be a baker.
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.
You’re very optimistic about our ability to divert 22km-diameter object moving at 70km/s .
DART smashed 680kg payload into a 780m-diameter Didymos changing its orbit.