We often think of the universe as being dauntingly
large, so much so that traveling to the nearest
star system, currently Proxima Centauri, seems
only just within theoretical reach and even
then, it will take many years to accomplish
As a result, the idea of actually colonizing
worlds that orbit other stars seems far in
the future, so far that we can only really
dream about it right now.
And when we look into the universe itself
for others that may have colonized multiple
star systems, we have yet to see any evidence
That should not be discouraging though, that
may simply be because civilizations are hard
to spot and we may yet find ones that have
colonized as our equipment gets more powerful.
But one thing that I think often gets neglected
in the debate over interstellar colonization
is that stars independently move through the
galaxy and surprisingly often they pass close
enough to us that colonization of any worlds
they may harbor could be far easier than colonizing
distant stars and planets.
It’s more a matter of just patiently waiting
for a wandering star to pass by, though I
personally also encourage proactively branching
It may seem like a very long wait to sit around
hoping for a star to pass by, but it makes
sense to view things in perspective.
The status quo of distances between other
stars and the sun was very different only
just 70,000 years ago.
Before I begin, this story illustrates well
how dynamic and interesting astronomy can
be, especially these days with our ever improving
equipment and understanding of the universe.
We did not know until recently that this past
encounter between the sun and another star
system even happened, and even the star system
itself that passed close by was only discovered
The star is called Scholz’s star, after its
discoverer, astronomer Ralf-Dieter Scholz.
In a 2015 paper by Eric Mamajek and colleagues,
links to all mentioned papers in the description
below, they report that Scholz’s star passed
so close to our sun 70,000 years ago that
it entered the outer Oort cloud.
Now, that time frame is interesting because
we were here back then.
We didn’t have recorded history yet, nor were
we probably doing much other than focusing
on raw survival, but homo sapiens was here
at a time when another star system was passing
less than a light-year away.
We may well be here still the next time this
sort of thing happens, see my video on this
channel about Gliese 710, a star that will
pass within the Oort cloud a bit over a million
years from now.
But it may happen sooner.
There is also now another star known that
may pass even closer than either Gliese 710,
or Scholz’s star.
This third star is known as HIP 85605.
This star may be either an M type dwarf or
a K type main sequence star, and is currently
at a distance, though this is really uncertain,
of about 18-28 light-years.
Actually, everything is uncertain with this
star, but in 2014 it was advanced in a paper
Bailer-Jones, link below, that HIP 85605 could
pass within .13 to .65 light-years from the
sun sometime between a quarter and a half
million years from now.
That would be extremely close, and would be
far deeper in the Oort cloud than the other
known future encounters will penetrate, but
again, the distances involved and size of
this star are not yet well understood and
subject to significant future revision.
But that wasn’t all, Bailer-Jones also noted
that many more known stars will pass close
to the sun, and in the past many have, the
number being about 40 have come or will come
within 6.4 light years 20 million years in
the past or future.
In fact, the star Gamma Microscopii passed
within 6 light years of the sun about 3.8
million years ago and would have outshown
the current brightest star in the sky significantly.
And this star is no pedestrian dwarf type
star, this was a G-type giant star.
That’s disconcerting, the idea that large
stars can pass close by.
The paper notes that if the wrong kind of
star happens to pass us in the future, it
could bathe the earth in deadly ultraviolet
light, and if it happened to go supernova
while close enough, well, let’s just say that
perturbed comets would be the least of our
Thankfully, nothing like that appears on the
slate any time soon, but there may also be
other such stars that are yet to be discovered
that may pass close by even sooner than HIP
85605, some estimates say that a star should
pass through the Oort cloud about every hundred
thousand years on average, and one coming
as close to us as Scholz’s star did, should
happen about every nine million years on average.
Scholz’s star is in actuality a double star
system, there seems to be a red dwarf primary
star and a brown dwarf secondary star.
And early humans wouldn’t have known this
star was passing by, even as close as it was,
it would have been too dim for the naked eye
to see, though it might have been occasionally
visible due to short term flares.
It’s even dimmer now at a distance of about
And, in so far as we know, it doesn’t have
any planets, so we probably didn’t miss much
with that one as far as colonizing it goes.
But the passage does beg an ominous question,
did it sufficiently disturb the Oort cloud
enough to send a hail of comets our way?
The models say probably not, and even if it
did, the resultant comets won’t get here for
about another 2 million years.
If we’re still here after another two million
years of technological development, we likely
will have intercepted those and melted them
down for raw materials.
But in the end, a star with planets passing
that close to the sun in the future may offer
the human race, and this is far future speculation,
an opportunity to colonize another star system
by virtue of it passing by us rather than
us going to it.
But that colonization would be sad, as our
colony would recede from us after the encounter,
growing ever more distant until eventually
meaningful communications would be lost.
Thanks for listening!
I am science fiction author and futurist John
Michael Godier and as a note to the viewers
asking about a KIC 8462852 update, I don’t
yet have enough solid material to make a video,
but I can say that the star continues to dip
and remain active.
More on that story in the not-too-distant
future and be sure to check out my books at
your favorite online book retailer and subscribe
to my channel for regular, in-depth explorations
into the interesting, weird and unknown aspects
of this amazing universe in which we live.