
That Interstellar Asteroid Is Pretty Strange - okket
http://blogs.discovermagazine.com/outthere/2017/11/23/interstellar-asteroid-mystery/
======
DanielleMolloy
Here is the random astronomer on Reddit claiming that the community didn't
rule out that it is an abandoned spaceship yet:
[https://amp.reddit.com/r/space/comments/7ealls/solar_systems...](https://amp.reddit.com/r/space/comments/7ealls/solar_systems_first_interstellar_visitor_with_its/)

"Astronomer here! I will never say this lightly, but we are, swear to God,
actually discussing with some seriousness right now what are the odds that
this was actually a spaceship. Which I 100% assure you has never happened
before in my memory with seriousness."

~~~
erikb
Why the hack do you assume it's abandoned? It can be full of lifeforms even
and we are just not able to see them, talk to them, etc. Imo at this point any
assumption is closing in too much. We don't have a definiton of "life" that
for sure would include extraterrestrial lifeforms that are not actors with
masks in star trek, right?

~~~
paulmd
Well, it's tumbling end-over-end which suggests that if it's a spaceship, it's
no longer in control.

The discussion around the possibility of it being a spaceship rests on the
idea that long thin cigar-shaped objects are the most efficient way to travel
in space because it minimizes your need for ablative protection from
interstellar dust/etc. But if you're tumbling end-over-end you've thrown that
advantage away, so presumably that's not a thing you would intentionally do.
And if you are assuming that this spaceship has shields or whatever, then
there is no reason they would be restricted to a cylindrical shape.

It could be a discarded booster stage or fuel tank, of course. Maybe they were
trying to drop it into the sun and missed. Or a a mass-driver shot (maybe they
finally took care of that pesky Russell's Teapot for us...)

The presumptive conclusion is of course that it's a natural phenomenon, but it
sure is a weird object, and unless we can find a way to catch it (or any
future objects) we will never know. Maybe a starshot probe could catch it?

~~~
semi-extrinsic
The really interesting prospect raised in that Reddit thread is that while the
velocity is likely wrong for an interstellar spaceship, it could be just right
for the spent and discarded deceleration stage of an interstellar spaceship.
In which case the spaceship would be arriving some time later...

~~~
valuearb
It's already passed pedigree with the sun. It is traveling slowly enough that
if it's a discarded stage the spaceship should already be here.

~~~
xelxebar
I'm assuming autocorrect helpfully fixed "perigee" to "pedigree" for you. It's
a nice little malapropism though.

Anyway, minor point but "perigee" usually means closest approach to _Earth_ ;
"-gee" is from the Greek for Earth (as is "geo-"). In the case of the sun, we
have the word "perihelion", and for generic orbits around an object, you
generally hear "periapsis".

And just for completeness, I'll mention that the counterpoint to periapsis is
apoapsis, with apogee and aphelion being the obvious specializations.

There are more words in this pattern for various different objects; Wikipædia
has all the gory details:

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

~~~
valuearb
Autocorrect figured out I meant that we need to make sure aliens have
sufficient pedigree before we deign to talk to them.

------
Voloskaya
> Occam’s Razor says it’s unlikely that the very first object we ever see from
> interstellar space just happens to be a spaceship.

Well, isn't this kind of self fulling thing?

Because we assume first that this is an interstellar asteroid, then the
following statement is "proven":

> Researchers had long theorized that space should be full of comets and
> asteroids ejected from other solar systems during their early days. Their
> models showed that planetary formation is a messy business, with many small
> objects kicked out as big proto-planets form. `Oumuamua is the first proof
> that they were right

And at this point, yes, it appears very unlikely that the first interstellar
object we meet would be artificial.

But if we start by saying we don't know what it is, then the above theory is
just speculation, and might be false (what if planeraty formation is a clean
process?). If the theory above can be false, then it could make sense that the
first interstellar object we encounter would be artificial, no?

It seems to me that Occam's Razor doesn't tell us much in this instance.

~~~
hyperpallium
Unfortunately, Occam's Razor can say whatever you want by fiddling the
_apriori_ probabilities. Here, the probability you need is how likely that
theory is to be true - just because it could be false doesn't mean it's 50-50.

If all the models show planet formation is messy, it seems reasonable to
estimate its probability as much greater than 0.5 (note that even if it's
0.9999, they still could be wrong).

~~~
Voloskaya
Totally agree. My point is just that I find it a bit weird/circular to use
Oumuamua as the `first proof` for a theory that is subsequently used with
Occam's Razor to demonstrate that Oumuamua is likely not something else.

------
splittingTimes
So why exactly can we not get a better look at it as it is leaving? With all
our earth- and spacebound telescopes [1] (some are sitting at Earth-Sun
Lagrange points) I would imagine we could. Being too far away behind the sun
seems an unlikely argument to me.

===

[1]
[https://en.wikipedia.org/wiki/List_of_space_telescopes](https://en.wikipedia.org/wiki/List_of_space_telescopes)

~~~
grkvlt
The only working telescope at a Lagrange point is Gaia [0] at Earth-Sun L2,
but it is an astrometry instrument, designed to measure the position and
brightness of various stars, rather than generic deep-space imaging. The
Herschel Space Observatory [1] is also at the Earth-Sun L2 point, and has a
3.5m IR telescope, but ran out of coolant in 2013 and is now defunct.
Interestingly, these are both ESA missions, not NASA.

0\.
[https://en.wikipedia.org/wiki/Gaia_(spacecraft)](https://en.wikipedia.org/wiki/Gaia_\(spacecraft\))

1\.
[https://en.wikipedia.org/wiki/Herschel_Space_Observatory](https://en.wikipedia.org/wiki/Herschel_Space_Observatory)

~~~
rsynnott
NASA was involved in Herschel to an extent.

------
kirykl
Seems like this is the same problem/discussion a distant civilization would
have with Voyager

~~~
kk_cz
Voyager is much smaller, though. Can someone with relevant knowledge tell us
if this object would be still detected if it was the same size as Voyager 1?

~~~
scruple
Would we have detected a Voyager-size or Voyager-like object entering our
solar system? I really, really doubt it.

------
michaelwiliamd
>It’s also our first direct look at an intact visitor (as opposed to dust
specks) from another solar system.

Would it not be possible to calculate the origin system based on speed,
trajectory, star positions?

~~~
dangerbird2
The problem is that the star positions change over time via galactic orbit.
'Oumuamua's trajectory appears to originate from Vega, but Vega would have
been at a different position in relation to our solar system back when
'Oumuamua was at the same distance from the Sun as Vega.

------
hectorlorenzo
These actually sound like last famous words.

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jfindley
Are there yet any credible theories for why we see so few of these? AIUI, if
we're correct about how planets form, there should be far more of these than
we're seeing. Is it that we're probably wrong about how planets form, or
there's something strange about our part of the galaxy, something else or do
we just have no clue?

~~~
Voloskaya
Estimate is that there might be about ~10 of these object passing through
every year, so it's not a lot to start with. In addition asteroids are
relatively small and hard to spot since they are inert. We managed to spot
this one because we were lucky it came so close to earth.

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Santosh83
Is there _any_ possibility we could launch a really fast space probe that
could overtake this object and report back, maybe within the next decade or
so? Do we have the technology now to pull alongside this rock (and it's going
to be slowing down)?

~~~
api
Probably. Strap a big overpowered upper stage behind a little lightweight
payload and you can fire something pretty fast.

~~~
valuearb
Unfortunately it's almost impossible at this point. The object passed pedigree
a while ago and is headed back out, earth is in a very poor position for an
intercept. The calculations I've seen say even if you use the largest possible
booster, the SLS (which doesn't exist now, won't exist for another 3 years, if
ever) it couldn't even get a small probe to catch up for a very long time, if
ever.

There may be options in using Jupiter for slingshot maneuvers to overcome our
bad positioning, and using super advanced hall effect motors, or project
slingshot type probes. But it seems pretty slim at this point.

UPDATE: The reddit thread has this comment "Not a chance. Velocity relative to
the sun is presently > 39 km/sec and relative to the earth is > 64 km/sec.
This is far faster than anything we have ever launched or even could plausibly
launch in the near future".

Which explains why you need Jupiter to redirect your probe so you can have it
go only 40Km/sec to catch up, rather than 65 Km/sec direct from earth.

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arnaudsm
Relevant XKCD : [https://xkcd.com/1919/](https://xkcd.com/1919/)

------
singularity2001
tell me it's no the vanguard of a galactic police squad coming to arrest
humans for universal misconduct

------
wruza
Say whatever you want, I know it is Silkie spaceship.

------
joering2
What's really shocking is the drawing from the article [1]

This Astroid was Discovered when already passed by the Earth!!

And was actually very close to it! While I am pretty certain Astronomers knew
it won't hit us, the amount of time it took to discover it would be way too
late for us to even hold hands and kiss our children goodbye!

[http://blogs.discovermagazine.com/outthere/files/2017/11/eso...](http://blogs.discovermagazine.com/outthere/files/2017/11/eso1737c.jpg)

~~~
valuearb
The earth gets hit by similarly sized asteroids every 30,000 to 100,000 years,
albeit not quite at this velocity. Average impact velocity for asteroids from
our system is 17 Km/sec, so about 2/3s the speed of this visitor. Either way,
it's not even close to an extinction event.

And "very close to it" is a misnomer. It came within 24 million kilometers of
Earth, about 60 times farther away than the moon is.

