
A Visiting Star Jostled Our Solar System 70,000 Years Ago - rbanffy
https://gizmodo.com/a-visiting-star-jostled-our-solar-system-70-000-years-a-1823954398
======
ninkendo
I'll take this opportunity to recommend Universe Sandbox[1], which is pretty
cheap on steam and worth every penny.

Turning on projected orbital lines in an N-body simulation of our solar system
and seeing what happens when you toss a star in there is _really_
enlightening... the rings all shift in tandem in a visceral way that really
helps me "feel" what happens.

There's a simulation that comes out of the box that simulates the
circumstances of the book "Nomad" (I haven't read the book) where a small
solar-mass rogue black hole drifts past the solar system at high speed. With
orbital path projections turned on you get to watch all the paths shift like
wobbling hula hoops as the unseen object drifts past. Most orbits remain
stable but very deeply shifted from where they were (earth's aphelion ends up
far out where Jupiter was, with its perihelion much closer than before...)

The effects described in the article are obviously less extreme, but the game
helps me get a sense of just how perilous our planetary orbits are and how
vulnerable to outside influences they can be.

[1] [http://universesandbox.com/](http://universesandbox.com/)

~~~
antisthenes
> Most orbits remain stable but very deeply shifted from where they were
> (earth's aphelion ends up far out where Jupiter was, with its perihelion
> much closer than before...)

That's incredibly terrifying. Although from what I see in the book
description, it focuses more on the drama aspect.

I wouldn't mind someone exploring the technical aspect in more detail, e.g.
what would be possible to do to prepare for such an event (if anything) and
how likely it would lead to the extinction of civilization.

~~~
Merad
The scenario described is almost certainly the end of human civilization and
the majority of life on earth. Assuming I’ve done the math right, an aphelion
of ~5 AU and perihelion of ~0.9 AU gives a highly eccentric (e = 0.69) orbit
taking 5 years.

I’m just guessing here, but I imagine each orbit would start with 6-8 months
of relatively normal temperatures as we made or closest pass by the sun, a
year or so worth of dropping temperatures, 2.5 years of deep, deep freeze, and
a year of slow warming as we approach the sun again. Each orbit is probably
going is probably going to see the planet spending at least 3 years _competely
outside the habitable zone_. I’d expect virtually all life as we know it on
the surface to die in the first orbit.

With enough warning we might be able to dig some deep facilities that could
harness geothermal energy to generate power and avoid freezing. They might be
able to use hydroponics or something to sustain themselves for a long time,
but to what end?

~~~
meric
There’s life beneath deep oceans that thrive on geothermal - I think it’s
possible some life can survive.

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24gttghh
I was going to ask if perhaps ancient humans saw this new red star and if it
drove them to an elevated state of being superstitious and chaos but:

>When Scholz’s Star was in the neighborhood, it would have been a 10th
magnitude star (red dwarfs are very dim). That’s about 50 times fainter than
what can be seen with the naked eye at night. Under normal circumstances, it
would be invisible. But because red dwarfs are magnetically active, it could
have briefly “flared-up” (i.e., V-band flares) to become thousands of times
brighter. The astronomers say it’s possible that the star was visible to our
paleolithic ancestors for a few minutes or hours if this rare flaring event
transpired at the time.

~~~
acobster
I was drawn to that passage as well. The author goes on:

> _Sadly, this star’s passing likely went unnoticed by our ancestors._

I mean, I _get_ it, but _why_ is it sad? Is it because it feels like a "missed
connection" with our ancestors? Tangential, but I feel like the answer to this
question connects with why people study astronomy in the first place, and I'm
just curious if others relate to this sentiment. :)

~~~
Heliosmaster
Sadly because our ancestors missed the opportunity to see such an event, as
rare as we think it to be.

~~~
d33
Actually perhaps it's better that way. Otherwise they could base some
superstitious thinking on it that would stick if we were unlucky enough and
there'd be yet another case of irrational thinking to be undone.

~~~
vanattab
I have never been able to understand why so many other scientists and
"rationalist" look back on humans early "superstitious" ideas with contempt.
To my mind these superstitious ideas are the beginning of the rationalist
mindset. These ideas are people's attempts to explain and understand how the
world works. I am certain that some of the ideas that many of us hold now will
be thought quite silly in a few hundred years.

~~~
rhapsodic
_> am certain that some of the ideas that many of us hold now will be thought
quite silly in a few hundred years._

Yes, like the theory that we're actually living in a simulation, espoused by
Elon Musk and other respected, ostensibly science-minded people.

It's basically Creationism in modern form.

~~~
dboreham
It isn't like creationism because it is based on some otherwise currently
unexplained observations such as quantum mechanical behavior and magic
physical constants. The idea is that these are exactly the sort of
observations you'd see if you were in a simulated universe.

Now if we were to observe new species being created in N days, for small
integer N, then I suppose your assertion about creationism would also hold.

~~~
prewett
Wouldn't a simulation have to have a creator? Unless you are postulating that
a Turing-complete simulator got itself together by random chance and, by
random chance, started simulating universe(s), one of which, by random chance,
happens to simulate beings that can imagine a simulator simulating themselves.
It seems like a simulation is a fairly strong evidence FOR a creator.
Hawking's quantum bubbles seem much more like what would happen without
intervention.

Also, creationism isn't limited to only 6 day creation, that's more of a
modern thing by people that insist on taking Genesis 1 (which is poetry)
literally. Early Christian thinkers postulated that 1 Genesis-day was actually
1000 years. Creationism just says that God created the world; how long it took
and how he did it are implementation details.

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optimalsolver
Isn't that around the time of the Homo Sapiens genetic bottleneck?

~~~
ddalex
I'm amazed at this coincidence, too.

~~~
eleitl
It can't have had sufficiently fast impact on Earth by disturbing orbits to
create impactors, given the distance.

~~~
JoeAltmaier
Isn't the article mostly about how it _did_ influence Oort cloud object
orbits? Thirty-six identified.

~~~
chasing
That's a minuscule number and "influenced" doesn't necessarily mean "aimed
them at the Earth." There's a lot of space out there which it takes things a
lot of time to move through. It takes the Earth a year to go around the Sun.
And the Oort Cloud is, like, 100,000 times further away from the Sun than we
are.

~~~
JoeAltmaier
They went into 'v' orbits, which as I understand it, means steep highly
elliptical orbits that come inside the Earth's orbit? Its a lot more crowded
in here.

~~~
chasing
I'm no space science maker person. So take this all with a grain of salt. But.

Halley's Comet takes 75 years to make an orbit. It goes out to about 35AU.
Let's call that 1 year per AU. That rough, rough number would lead one to
conclude that anything from the Oort Cloud moving at a similar speed could
take, say, 100,000 years to get here even if it was aimed at us. If triggered
by something 70,000 years ago, we'd still have a bunch of millenia to prepare.

Anyway. I'm sure I'm completely wrong.

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ericfrederich
Wikipedia says this is 17-23 light-years away. So it moved between 16.2 and
22.2 light years in 70k years. This means relative to us it is moving an
average of 0.0231% to 0.0317% the speed of light.

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everdev
Reminds me of an Ask Ethan where solar systems can get slingshot out of their
galaxy with planets in tact: [https://medium.com/starts-with-a-bang/ask-ethan-
can-stars-es...](https://medium.com/starts-with-a-bang/ask-ethan-can-stars-
escape-from-the-galaxy-with-planets-intact-e8b6f4bf73ef)

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flukus
> Around the same time our ancestors left Africa, a dim red dwarf star came to
> within 0.8 light-years of our Sun

So that's within the Oort cloud. If this happened again should we be more
concerned about the star disturbing our Oort cloud or about us travelling
through the other stars Oort cloud?

------
c-smile
Again: as sooner we start our resettlement to other star systems - the better.

~~~
vkou
What about the opportunity cost? What about the long-term?

Maybe we should make our ecological footprint steady-state sustainable, first.

~~~
squozzer
I think your idea is more practical, given the state of spaceflight technology
- BUT, should it succeed, then little incentive would exist to leave Earth.

Given the impulses of people in power now, coupled with whatever steps the
future takes to make Earth sustainable, it's hard to imagine a future
government allowing people to leave. It would, after all, be setting up a
competitor. Paranoid, you say?

Imagine an English king c. early 1600s having a vision of the descendants of
his loyal colonists rebelling 170 years later. And the nation founded by the
rebels eclipsing England 130 years after that. History might have turned out
differently.

The good news is that thanks to France and Spain, the English king had little
choice - he had to oppose France and Spain everywhere he could, or risk losing
strategic advantage.

~~~
wallace_f
>It would, after all, be setting up a competitor

There is nothing paranoid about that.

Evolution is not some magical 'forward' direction where every species becomes
more technologically capable, or even more dignified.

It might be true that our species' now has a limited opportunity to become
multi-planetary.

The first person to get to the moon was Korolev, and he would have continued
rotting in a gulag had the urgency for a space program not been there.

And before you say the US is so much unlike Russia--our competing Vanguard
program should, from an industrial standpoint, have won, but it was a massive
failure, and embroiled in politics of its own.

Humanity needs competition to keep us honest, in the same way that the
veracity of ideas needs to be tested by experiment to keep them honest.

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nsxwolf
Do large, bright stars ever pass that close? What would that look like?

~~~
lisper
> Do large, bright stars ever pass that close?

Yes, but it's extremely rare.

> What would that look like?

Not much. The Scholz flyby was at 0.6-0.8 light years, the same order of
magnitude as the distance to Alpha Centauri. It would just look like a star,
probably not even a particularly bright one.

~~~
mtgx
Alpha Centauri is 4.37 light years away. Or did I misunderstand your comment?

~~~
lisper
Hard to say. Yes, Alpha Centauri is indeed 4.37 LY away, though that kind of
precision is irrelevant when talking about orders of magnitude (OOM). Two
numbers are considered to be the same OOM if the absolute difference of their
base-10 logarithms is less than 1.

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kazinator
Immediately upon clicking this, I typed Ctrl-F followed by "artist's
depiction". The page didn't disappoint. :)

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Santosh83
I wonder what its velocity is in relation to the sun. Twenty two light years
in 70,000 years seems rather fast!

~~~
maze-le
It seems to be quite fast, but not exceptionally. Lets do a quick calculation,
and neglect all aspects of proper stellar kinematics -- Our sun has traveled
quite some distance itself during the 70000 years, I don't properly described
that motion itself, so take everything with a grain of salt:

Lets call the speed difference of the star with respect to our sun `Δv`

    
    
       Δv = 20 [ly] / 70 000 [y] = 0.000285714 [ly/y]
    

Now, lets convert the unit `ly/y` into a unit that we can relate to, to get a
grasp on it: 1ly = 63241.08AU[1].

    
    
       Δv = 0.000285714 [ly/y] = 18.0688 [AU/y]
    

18 AU is about the perihelion of Uranus, a bit smaller still. So the star
traveled on average, with respect to our sun, about the smallest distance
between the Sun and Uranus in 1 year. To put that in perspective:

    
    
       Δv = 18.0688 [AU/y] * 149597900 [km/AU] / 31557600 [s/y] 
          = 85.6550 [km/s]
    

The LSR[2] is about 220 km/s. The Suns deviation from this value is about +14
km/s[3]. So an object with Δv of about 85.6 km/s is quite fast in comparison.
But this is still nothing compared to hypervelocity stars, wich can be more
than 1000 km/s faster and are exceeding the escape velocity of the galaxy.

\------

[1] : 1 AU (Astronomical unit) is the average distance from Earth to Sun.

[2] : Local Standard of Rest -- average speed of our stellar neighborhood
through the galaxy.

[3]: [https://arxiv.org/abs/1411.3572](https://arxiv.org/abs/1411.3572)

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tambourine_man
I have a problem clicking on Gizmodo ever since I read an article on what was
essentially a moto perpetuo machine presented as a breakthrough. Do we have a
better source for the news?

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john-adword
Nice information

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bugs_bunny
My guess is that the Oort Cloud is where the mothership turned off its
interstellar drive.

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TomK32
> orbits that are very exaggerated, and with a characteristic v-shape

v-shape, we all know where this will go to...

