It's the Pak!
It's official: the Asteroid 1I/2017 U1, aka "‘Oumuamua", which screamed through the solar system in October 2017 is an interstellar object. And a very strange one at that.* The 400 metre long asteroid is moving fast – 38.3 km/second is its current sun-relative velocity – and has already passed Mars' orbit after sling-shotting …
I wish we were able to examine it. Such an endeavour would have required a small automated science craft, atop of a very powerful rocket, ready for launch at a very short notice. IMO it is unlikely our governments would choose to spend tax money this way, if they can buy votes instead ...
In one of the papers on this interstellar object, the authors estimate that there are about 1000 of these objects entering (and leaving) the Solar system per year, so about three per day.
They're obviously interstellar buses, run by TfL.
I wish we were able to examine it. Such an endeavour would have required a small automated science craft, atop of a very powerful rocket, ready for launch at a very short notice. IMO it is unlikely our governments would choose to spend tax money this way, if they can buy votes instead
I think these objects are rather common, it is just that only within the last few years have astronomers had the motivation and equipment to look for small objects outside of the solar system's orbital plane. Computer simulations of the Oort cloud show that the majority of comets are ejected from it, and it most solar systems have an Oort cloud, then interstellar space must be teeming with comets. So, a bit like buses, there will be another one along in a minute.
Not a rocket scientist, but such a small body with no gravity well and moving at such speeds. I'd think the best we could do is a flyby, which hardly seems worth it.
As for government spending, the majority of it goes to social programs (pensions, healthcare, poverty alleviation), so it is going to be hard to convince pols to free up money from those programs.
"Such an endeavour would have required a small automated science craft, atop of a very powerful rocket"
Either a very small probe indeed, or a more powerful rocket than we actually have. The only way we could get something up to similar speeds to this rock (or dormant spacecraft or whatever it is) would be with multiple gravity assists, which we don't have time for, and anyway, it's moving well outside the plane of the ecliptic, so you'll need a massive plane change manoeuvrer as well.
Basically, there was no way we could get anywhere near this, even if we'd know a couple of years in advance.
The pic looks more like a Sperm whale that has suddenly been called into existence several miles above the surface of an alien planet.
And since this is not a naturally tenable position for a whale, this poor innocent creature has very little time to come to terms with its identity as a whale before it then has to come to terms with not being a whale any more.
The article says "‘Oumuamua varies in brightness by a factor of ten as it spins on its axis every 7.3 hours”.
To me that suggests it is going end over end like a spinning knife - and the viewing angle is approximately end on. Maximum brightness when all of one side is visible - minimum when only a tip.
This would give simulated gravity at each end, in the hollowed out living quarters.
Like around: 1E-4 G?
You need it spinning at ~ 0.5 rpm or thereabouts for it to be usable for artificial gravity (it is quite funny to see all the sci-fi trying to simulate artificial gravity as they never spin it to anything near the speed you need to get anywhere with it).
At what radius?
I have not checked your maths, but your reference to sci-fi leads me to believe you are saying that is the threshold - apologies if you've taken the trouble to work that out for the object; the BBC article said yesterday that they have not been able to work out the exact dimensions.
It's been a while but I'm pretty sure we need to multiply the radius from the centre of mass to give you the force (for a constant period). The same number of rotations per minute translate to higher forces for long objects :)
... how long it'll be before we have the technology to catch up with it and give it a good going over. One also wonders what we may have learned, if we had that technology today. Methinks the human race has lost a marvelous opportunity that we may well never get back.
During the meanwhile, we wasted all that money on what, exactly?
(Don't bother answering, I already know, and I'm depressed enough as it is.)
Roughly never would be my guess as to when we might catch up with it. However, it's pretty much at the limit of the speed needed to leave the solar system, so it might end up being captured and in orbit around the sun, in which case we'd thereotically be able to send a probe.
The fastest man made objects are the Vogager probes which are doing about 17KPS, having taken advantage of a once every ~200 year alignment of the planets to gravity boost past every one of the planets in the outer solar system. This obviously is also limited to going in the direction the planets are aligned, rather than the direction that you might want to go, such as after a chunk of rock that's come from outside our system doing 40KPS.
Realistically, there will be plenty more opportunities at similar things. We've only been seriously tracking things in the system much smaller than planets for the last 50 odd years so who knows how many things will show up in the next few hundred years?
A solar sail and/or ion drives and some nuclear power/solar power can help get to just about any speed until you run out of fuel.
However, they don't do so "fast", and when it comes to rendezvous you either need to plan ahead (no chance here as we saw it too late), or go faster!
I suggest (as always) purchasing Kerbal Space Program if possible, and having a go with the "Toy" sized solar system, but very much "real" type physics problems involved with building space craft.
By the time we have the technology to chase it we will be able to give it a going over from afar. I would imagine a moon base alfalfa (they will be growing their own) will be able to give it a fairly hefty whack with a laser or three and get a good idea of its make-up. Chasing it and attempting to land might prove a little more expensive and not much more illuminating.
I still enjoy listening to Oumuamua once in a while. It is remarkable how well the first half has survived its extraordinarily long journey, probably because it is indeed metal rich. Just a shame it doesn't have an Interstellar Overdrive.
Seriously though, what are the chances of an asteroid travelling that far and not falling into the sun, and not just continuing on past it. It's almost like it was very carefully planned
Not many things fall "into" the sun. You need to loose gravity when already moving/in orbit. Thus it takes more energy to do so.
We are already not in orbit/hurtling through space relative to the earth. So "falling" towards the earth is easy for us... but do we fall towards the sun? Slowly, while in orbit along with the earth... but we are moving so fast, we "miss" the sun each year.
Likewise, this object is hurtling through space, the sun is tiny, compared to the 360 degree space of choosing any angle to aim for. (An example of this, look into the sky, while we may be able to pinpoint stars, to "aim" at one requires effort).
So the object will go somewhere around the solar system, but "hitting" something is a low chance. Being deflected by gravity of the sun and planets is very high chance, and generally things get flung out (see dark matter and Galaxy halos... though both still unexplained fully).
"Seriously though, what are the chances of an asteroid travelling that far and not falling into the sun, and not just continuing on past it. It's almost like it was very carefully planned".
That a big extrapolation from one example. Maybe a thousand have fallen into the sun this week. We just haven't seen them. Expectation is that newer methods of scanning the sky will mean we should be spotting a lot more interstellar visitors in the coming years
Another interpretation would be a roughly spherical rock of very dark colour, but with a bright red stripe on it. That could account for the brightness variation, and the only way of distinguishing it from the baguette model would be timing stellar occultations which, for whatever reason, does not seem to have been done.
If you drive from Dunedin, New Zealand across the Taieri plains and up and over the rock and pillar range as you descend towards Middlemarch in the Strathtaieri plain there is a large spherical looking boulder on the right of the road. Except it has been hollowed out by the prevailing wind and is dish shaped inside. Just one of the quite impressive rock outcrops which gives the range its name.
I understand that these days they run cross country skiing trips on the tops which are fairly flat to rolling with gullies.
There are mountain wetas up there (giant flightless crickets) which freeze solid in the winter then thaw out and wake up again quite happily.
Possible but very unlikely, based on flight path analysis:
"Here we investigate the possibility that the asteroid 1I/2017 U1 actually is a Solar System object, currently expelled from the Solar System by the recent encounter with a Solar System planet. We show that this possibility is extremely unlikely and that 1I/2017 U1 really is an interstellar object."
From your source:
"In conclusion, unless one invokes the existence of another, yet unknown, planet on
the path of the asteroid assumed to come from the Solar System, one is forced to
conclude that the latter came directly from the interstellar space."
There is something very large beyond the Oort cloud which causes much damage each time it ventures closer sunward - it's orbit, mass and nature are unknown. It could even be a brown dwarf. This is a shard from a large shattered mass flung far out long ago.
Biting the hand that feeds IT © 1998–2019