
First possible interstellar object detected in our solar system - herodotus
https://www.nasa.gov/feature/jpl/small-asteroid-or-comet-visits-from-beyond-the-solar-system
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mustacheemperor
Anyone else thinking of Rendezvous with Rama by Arthur C Clarke right now?

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jboggan
I'm thinking more like The Expanse.

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dfischer
I just finished the show (season 1 and 2) and it’s the best sci-fi I’ve seen.
I find it more epic than BSG. I’m so happy I watched it. I am considering
picking up the books now. The science is on point. Flip and burn baby!

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TheSpiceIsLife
I wish I had read the books before I watched the TV series. Doing it in the
reverse order has made me fairly unmotivated to read, I'm a few chapters a in
to the second book and not sure I'll continue.

Having said that, I've been fairly unmotivated to read anything recently due
to working long hours and recently having rescued a dog.

Let Ne know how you go with it.

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TeMPOraL
I started reading the books only after the first season, and I'm very happy
that I've started with the show first - now I read all Avasarala's lines with
Shohreh Aghdashloo's voice.

(In general, I find reading after watching a much more pleasant experience -
if I read a book first, I form my own image of the characters, which then
usually clashes with what's in the movie. If I do it the other way, I just
cast the characters I saw in the movie into the book.)

That said, do continue reading - the novels only get better with time, and
there's plenty of awesome waiting that the show is nowhere near reaching.

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lorenzhs
I wish show-Avasarala was as abrasive and foul-mouthed as book-Avasarala. That
would make it even more fun, but would probably make the show harder to show
on TV ;)

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TeMPOraL
I agree. Not everyone likes it, but I do appreciate the amount of f-bombs she
drops in the book. AFAIK though, the issue was not only with family-
friendliness of the show, but also with the actress not liking to swear.

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Cyphase
The Wikipedia article for this object:
[https://en.wikipedia.org/wiki/A/2017_U1](https://en.wikipedia.org/wiki/A/2017_U1)

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Yetanfou
A probe sent out by some remote civilisation, it is on its way through our
part of the Milky Way galaxy. It used Sol as a source of gravity to slingshot
itself on its way in the direction of Pegasus. It also did some measurements
while it was at it, even though this system is not its final destination.

Yes, totally made up but in theory it would be possible.

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Cyphase
> okket: A remote civilisation that has no problem waiting hundred thousand
> years or longer for a probe to reach its destiny.

> pavlov: At 44 km/s, the object is travelling slightly faster than Pioneer
> 10. Seems too slow for an interstellar probe?

> QAPereo: A probe should show signs of acceleration, not freefall... unless
> you anted the probe to be stealthy. That is a disturbing thought.

Of course it has FTL, but they want to observe us for an extended period in
our natural state, not riled up by an FTL object moving through our system and
parking in orbit.

They also wanted to see how long it would take us to detect it. I'm not sure
how well we did.

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chmod775
> I'm not sure how well we did.

Well it's already leaving again after it completed its maneuver around our
sun, and we haven't even a proper telescope pointed at it yet...

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alvern
91800 kmh per hour incoming, 158400 kmh outgoing. This space puppy just gained
66600 kmh from passing through our solar gravity well. Not particularly
relevant, but very interesting!

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arnaudsm
Prepare for thousands of clickbaity articles on mainstream media in the next
few days.

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itg
Might not be interstellar
[https://mobile.twitter.com/AscendingNode/status/923223634386...](https://mobile.twitter.com/AscendingNode/status/923223634386206720)

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okket
Please also read

[https://groups.yahoo.com/neo/groups/mpml/conversations/messa...](https://groups.yahoo.com/neo/groups/mpml/conversations/messages/33145)

> AscendingNode's tweet is in error: It's using the basic find_orb fit (which
> tries to fit the object's observations to a parabolic orbit) without taking
> into account the fact that it COULD be interstellar.

> You'll notice quite clearly, that in the follow-up tweets they make, that
> they give residuals in the orbit on the order of 6-9 whole arcseconds. It's
> quite bothersome that everyone I've been talking to has been re-quoting the
> tweet all day.

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arbuge
Technically, it would be the second. First in solar system was Voyager I:

[https://en.wikipedia.org/wiki/Voyager_program](https://en.wikipedia.org/wiki/Voyager_program)

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misnome
It’s an interstellar object, but not _in_ the solar system (it used to be, but
wasn’t interstellar until it left)...

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IIAOPSW
I like to imagine some alien civilizations version of Voyager 1. Perhaps they
sent us their own golden record with difficult to decipher pictographs and
samples of pictures and music.

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justinjlynn
If it is, given its trajectory, it's probably not meant for us. I would be
nice to keep an eye on it though -- it'd be fun to get a complete scan and
hope it's doing the same in return. It's too bad it's likely too late to
rendezvous with it and get some samples.

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_jdams
Off topic but can someone answer this for me? Are the stars in our night sky
part of our galaxy or no? It seems such a stupid question to ask, but when I
look online it says we have one star, our Sun, whereas other galaxies have one
or multiple - for instance a galaxy with two stars would be called a Binary
System.

So where are the stars in our night sky? Are they even further away than
Uranus, Neptune.., but so bright we see them anyway?

EDIT: Thanks, all! Makes sense.

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1_player
Either I didn't get your question, or you're a bit confused about the
structure of the universe. Not a problem.

There's Earth, it's a planet orbiting our star, Sol AKA the Sun, in our solar
system. A star has plenty of bodies orbiting around it, dust, asteroids,
planets, so the whole group is called a solar system.

There's other stars "next" to us, which in turn have dust, asteroids and
planets orbiting around them. So they also are solar systems, since all stars
have stuff orbiting around them.

Stars (/solar systems) tend to cluster together in a galaxy. A galaxy is
composed of billions of stars.

Earth/our Solar system is in the Milky Way galaxy, so most of the stuff we see
in the sky are stars that are not very far from us and/or part of the Milky
Way galaxy.

The closest galaxy from ours is Andromeda, which is in turn composed of
billions of stars, and countless planets.

So, the order is planet (Earth) -> star (Sun) -> (grouped into a) solar system
-> galaxy (Milky Way)

Binary systems are solar systems which do not have a single star, but they
have TWO! and these stars orbit each other. A galaxy has millions of binary
systems (not sure how rare they are)

Uranus, Neptune, etc. are part of our solar system, so yeah, the stars you see
are farther beyond.

EDIT: apparently I'm a bit confused as well, as star/planet groups are called
planetary systems, and only ours is called the Solar System (from Sol/the
Sun). The more you know.

Does this help and answer your question?

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dsr_
This, and also:

You can see some other galaxies with the naked eye, but not make out any of
the stars within them.

[https://en.wikipedia.org/wiki/List_of_galaxies#Naked-
eye_gal...](https://en.wikipedia.org/wiki/List_of_galaxies#Naked-eye_galaxies)

Note that the Magellanic Clouds are basically orbiting our galaxy, and that
the next closest independent galaxy is Andromeda, 2 and a half million light
years away.

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gpvos
Our asteroid detection system is still very pitiful if a 400m large object is
only detected four days _after_ its closest approach.

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retSava
"closest approach" is very unquantified, and 400 meter is a very small object
in a large space. It's a hard problem, probably not very prioritized either.

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sizzzzlerz
Perhaps it's a starseed, wandering between the rim of the galaxy and the
galactic core. To be closely followed by an Outsider ship.

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rakkhi
Good luck commander

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Jach
Has anyone done the calculation yet for what would have happened if it
collided with Earth?

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QAPereo
[http://impact.ese.ic.ac.uk/ImpactEffects/](http://impact.ese.ic.ac.uk/ImpactEffects/)

Have fun destroying Earth!

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spiznnx
I just ran it, the earth is fine :(

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QAPereo
Have some fun with hypothetical Relativistic impactors, it’s a blast. :)

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petraeus
The is the best way to disguise a probe and the fact it came from above the
elliptic might mean the aliens wanted to make sure it wouldnt collide with any
natural bodies

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mxuribe
This surprised me at first, because i thought Halley's Comet was also
interstellar...then looked it up, and sure enough its not...So, yeah for new
things!

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phaemon
Halley's comet returns every ~75 years. How could it possibly be interstellar?

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b0bdog
Is it not possible for the sun to capture an interstellar object?

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Grangar
Would it be possible at all to intercept it for analysis?

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throwanem
It's moving far too fast in the worst possible direction, and it's already far
too far away.

If we'd known it was coming, we could in principle have gotten something out
to its point of closest Earth approach, but the object's velocity means even
that would've been a flyby with no possibility of rendezvous outside possibly
an impactor.

As the matter stands today, anything we'd send after it would have to overcome
a velocity disadvantage of something like 40 kilometers per second - in other
words, traversing the diameter of our planet three or four times every second
- on a vector pointed near as nevermind to straight away from us. That's not
something our propulsion technology is so far even close to being able to do.

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b0bdog
That doesn't make sense. If the Earth is 12,000km in diameter, surely it will
take a few minutes to traverse and not multiple times per second?

Edit: Oh never mind, you meant the velocity needed to catch up with it.

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throwanem
Of course you're right. Evidently I cannot accurately exponentiate before
coffee!

But, yes, the velocity difference is a killer. The closest we've ever come was
the Apollo-Saturn stack, and even that only had ~9km/s left over after
reaching escape velocity.

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rbanffy
It'd be great if we had some general-purpose probes that could be redirected
to, at least, do a flyby.

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danieldrehmer
False. Any piece of gold in our planet is an interstellar object.

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QAPereo
_The object approached our solar system from almost directly "above" the
ecliptic, the approximate plane in space where the planets and most asteroids
orbit the Sun, so it did not have any close encounters with the eight major
planets during its plunge toward the Sun. On Sept. 2, the small body crossed
under the ecliptic plane just inside of Mercury's orbit and then made its
closest approach to the Sun on Sept. 9. Pulled by the Sun's gravity, the
object made a hairpin turn under our solar system, passing under Earth's orbit
on Oct. 14 at a distance of about 15 million miles (24 million kilometers) --
about 60 times the distance to the Moon. It has now shot back up above the
plane of the planets and, travelling at 27 miles per second (44 kilometers per
second) with respect to the Sun, the object is speeding toward the
constellation Pegasus. _

Sooooo cool! I wonder if the system of origin will eventually be determined?

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nawgszy
I doubt that's possible, although it would be very interesting.

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ccozan
"The CNEOS team plotted the object's current trajectory and even looked into
its future. A/2017 U1 came from the direction of the constellation Lyra,
cruising through interstellar space at a brisk clip of 15.8 miles (25.5
kilometers) per second."

So we have an origin. However they don't give the error margin so is probably
not possible to pin point the exact origin without further calculations.

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mongol
That it passes the ecliptic from that angle, that close to the sun, feels
"deliberate". Like aiming for bull's eye on the solar system, from above. Iss

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mkl
It's not deliberate, it's gravity. The sun has been pulling this object
towards itself, because that's how gravity works.

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ant6n
In space, the gravity well we more likely create big orbits. Since there's no
air slowing objects down, they won't all fall down to the sun.

For example, it's very energy intensive to go visit Mercury.

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mkl
Right, but that's for objects travelling more tangentially. An object
travelling kind of towards the sun will get redirected more towards the sun,
when the sun is the largest nearby mass.

It's unlikely that an object would be pulled right into the sun though, just
redirected by its close encounter so it flies off again in another direction.

