
Plan to Send Probes to the Nearest Star - laser
http://www.scientificamerican.com/article/100-million-plan-will-send-probes-to-the-nearest-star1/
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microtherion
There seems to be quite a bit of handwaving there. So a "gram-scale" space
probe is supposed to contain (1) enough shielding to survive 20 years of
travel at 20% of the speed of light (2) sensors good enough to capture useful
data during the fraction of a second the probe will be in a decent range of
the target and (3) communication equipment to transmit the results back across
4 light years?

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mrfusion
Keep in mind there will be thousands of them. even if most get destroyed at
least a few would make it.

Perhaps they could travel single file and block instelar debris for each
other. And pool their data to effectively get a longer exposure.

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madaxe_again
Additionally smaller craft present a smaller target. You could tip them with a
few inches of depleted uranium, which would make a reasonable ablative shield.
Maybe. Either way it's an engineering problem, rather than a physical
impossibility as others here are saying.

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pif
How could you stay within _gram-scale_ with a few inches of uranium shielding?

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madaxe_again
999g! You'd also stack it with voids, works better to slow projectiles.

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jimworm
A several-gram spacecraft travelling at relativistic speeds would pack quite a
punch. Definitely the most dangerous piece of space junk ever created. It's
interesting to imagine making our first contact with intelligent extra-
terrestrials by causing a small Tunguska-like event.

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ourmandave
_The spacecraft themselves would be essentially invisible: A gram-size
interstellar probe striking the Earth’s upper atmosphere at 20 percent the
speed of light would release roughly a kiloton of energy, indistinguishable
from airbursts produced by meter-scale space rocks that regularly pepper our
planet at a rate of about once per year._

So they also want to fund an array that would start looking for a robot impact
from other civilizations and recognize it as such.

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melloclello
Doesn't the interstellar medium effectively turn into alpha radiation at
significant percentages of the speed of light?

[http://www.antipope.org/charlie/blog-static/2016/08/san-
trom...](http://www.antipope.org/charlie/blog-static/2016/08/san-trombone-
exoplanet-reality.html)

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pif
No, particles don't change their nature depending on their speed. Furthermore,
you realize that speed is always _relative_ to something (especially in open
space, when there's no conventional reference system as it happens in day-to-
day talking on Earth)? So, would you say that a particle can be a neutrino
w.r.t. a galaxy and an alpha particle w.r.t. another remote galaxy?

Or that it can be an electron w.r.t. a star and a beta particle w.r.t.
another? ;-)

> we have a technical term for an ionized helium nucleus travelling at roughly
> 2% of the speed of light—6000km/sec—we call it an alpha particle.

Technically, an helium nucleus is an alpha particle, independent of its speed.

Edit: an helium nucleus with _two_ neutrons is an alpha particle. An helium
nucleus can exist with just one neutron.

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melloclello
I thought that was a pretty choice line. Relax, I think we both know what
Charlie actually means.

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exabrial
The sun? Seems a little expensive.

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ceejayoz
$100M for a space mission seems inexpensive, let alone for our first
interstellar one. Sending a few people to low Earth orbit costs $70M/person on
Soyuz.

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jessriedel
$100M is just the amount promised by the billionaire philanthropist. The
mission itself would cost several orders of magnitude more.

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hoodoof
I would love it if this was anything but science fiction but it's not. I have
friends who liken traveling to the stars to the journeys of people like
Columbus, but people just have no idea of the mind boggling, mind bending, if-
you-think-you-grasp-then-you-really-don't distances involved in travelling
even to the edge of our own solar system let alone to the nearest star.

It might happen but will never succeed.

Complete no.

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guard-of-terra
On Earth, the distances are similarly huge but still manageable.

For example, from me to Latin America 7000 times of what I walk every day from
and to work. So in my daily walks that's 20 years worth of walking! Or 40
years for both-ways trip! And yet I've been there.

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gpvos
Space is big. Really big. You just won't believe how vastly, hugely, mind-
bogglingly big it is. I mean, you may think it's a long way down the road to
the chemist, but that's just peanuts to space. [Douglas Adams]

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dzdt
Except that $100 million isn't how much it would cost, its how much that has
been promised. To actually send a probe would take several orders of magnitude
more money; the amount being quite uncertain because the technologies are not
yet developed.

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ourmandave
_At an estimated present-day price of approximately $10 per watt of laser
power, building and operating Breakthrough Starshot’s 100-gigawatt array today
could cost as much as $1 trillion._

They're hoping the cost would come down if the tech to build it becomes a
cheap-to-produce commodity, like Tesla batteries.

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wiz21c
Call me a cynic but... When a philantropist invest so much money in a project.
Does he make some return on investment (money, intellectual property, etc.) or
is is absolutely real philantropy ?

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pc86
Directly and financially, certainly no. But it's (usually) good press, (most
would say) a good goal, and if it works out because of this $ the
philanthropist is famous for helping fund it.

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jamesjyu
Dark Forest anyone?

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thatcherc
Yeah, especially with the tri-solar system they're aiming at. At least our
probes wouldn't be as menacing as the Droplet though!

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mxuribe
Even if the feasibility of these types of missions is low/improbable, its nice
to read about them. They stir the imagination, and create fodder for space
travel dreams. and, that's not so bad. It's that, or our children will be
interested in becoming only sports figures, actors, engineers for social media
companies only interested in more clicks/engagements of advertisements (and
not addressing real worldly problems), or worse. ;-)

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sreejithr
So would Yuri Milner get to own the couple of patents that would come out of
this project?

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jharohit
It's very interesting and odd that a few months ago such an elite group came
together to announce this trip and then now a new paper has announced finding
of a habitable planet around the sister star system? I sound like a conspiracy
nutjob but these seem like highly coincidental announcements..

