
A large asteroid recently flew close to Earth - herve76
http://www.businessinsider.com/asteroid-flyby-nearer-than-moon-2017-1
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jessaustin
In case one prefers not to get astronomical news from "Business Insider":

[http://www.space.com/35265-newfound-asteroid-buzzes-
earth-20...](http://www.space.com/35265-newfound-asteroid-buzzes-
earth-2017-ag13.html)

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david-given
Autoplay video (with sound).

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DrScump
...if you have Flash enabled. The video adds nothing, BTW.

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aggie
My favorite proposed method of asteroid deflection:
[http://www.planetary.org/explore/projects/laser-
bees/](http://www.planetary.org/explore/projects/laser-bees/)

The idea is to ablate material off of one side of the asteroid using lasers
and/or mirroring sunlight to redirect its trajectory. This is better than
using a nuclear bomb which risks fragmenting the asteroid. If you intercept
early enough it doesn't take much of a change in trajectory to miss Earth.

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halspero
There are whoppers out there capable of resetting civilisation. Do we have to
have a small city destroyed before we design and build the technology to avert
all future impacts?

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astrodust
What technology could avert this sort of disaster?

The USA is apparently retiring from the business of all things progressive and
space-oriented, so someone else will have to take up the torch. Right now it
looks like the only country with the resources and willpower is China.

I hope some states like California can pitch in and save NASA by funding it
directly before it's thrown in the garbage.

~~~
gooseus
I agree, though the fact still remains that most funding will go to novel (and
yes, important) scientific research rather than civilization-saving (and way
more important) asteroid defense.

On the importance... if human civilization discovers the precise nature of the
cosmos and no one is around in 100 years capable of learning about it, does it
matter?

Given the current political and social climate I think it's a lot more
pragmatic to learn how to organize and preserve our knowledge such that it's
as easily decoded and readily available as possible on as large a timescale as
we can manage.

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dTal
I'll quote one of the most insightful comments I've read on HN:

"Most of our physical tech stack is read-only executable code: there isn't a
civilizational "source code" that shows from first principles how to build up
to our current technology layer. For that matter, not even from first
principles to turn of the 20th century technology level."

([https://news.ycombinator.com/item?id=12824828](https://news.ycombinator.com/item?id=12824828))

~~~
halspero
Here is James Burke on this topic:

[https://www.youtube.com/watch?v=PeROEoimj7I](https://www.youtube.com/watch?v=PeROEoimj7I)

And here's Primitive Technology man:

[https://www.youtube.com/channel/UCAL3JXZSzSm8AlZyD3nQdBA](https://www.youtube.com/channel/UCAL3JXZSzSm8AlZyD3nQdBA)

(Should we leave his videos lying around on clockwork tablets?)

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toodlebunions
A regular occurrence

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life2hack
Well, it was small, but should have been spotted.

~~~
mitchty
Spotted by what or who exactly? If we want to see asteroids we need satellites
in orbit around the sun monitoring our blind spots (things coming at us from
the sun). Until then we'll never be able to spot things in all circumstances.

It also was spotted: A smallish asteroid zoomed past Earth this morning (Jan.
9), just two days after scientists first spotted the space rock.

Even assuming we had perfect alerting and this was a problem, what action
should have been taken considering this is a common occurrence?

~~~
jessriedel
Asteroids are identified and tracked with radio waves, not visible light, so I
don't think sun glare is a major issue.

~~~
mitchty
Radio only works for relatively close asteroids.

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

Which was sadly cancelled:
[http://www.dailymail.co.uk/sciencetech/article-3255059/Nasa-...](http://www.dailymail.co.uk/sciencetech/article-3255059/Nasa-
pulls-plug-killer-asteroid-hunter-Sentinel-mission-set-search-dangerous-space-
rocks-loses-30-million-support.html)

But the principle was based off infrared: [http://aviationweek.com/space/ball-
aerospace-ramps-sentinel-...](http://aviationweek.com/space/ball-aerospace-
ramps-sentinel-asteroid-mission)

The canadian satellite also uses light:
[https://en.wikipedia.org/wiki/Near_Earth_Object_Surveillance...](https://en.wikipedia.org/wiki/Near_Earth_Object_Surveillance_Satellite)

Visible light is only one fraction of the spectrum, infrared is far more
valuable for detection. Most asteroids are detected via passive observation.
Radio waves are not conducive to detecting asteroids.

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jessriedel
My mistake. Thank you for the correction.

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jessriedel
FYI, my understanding is that all the asteroids capable of posing an
existential threat to humanity are known and tracked. Smaller asteroids like
this one are not, but there is an upper bound on the possible damage they can
do, and the damage is pretty small in expectation (i.e., when weighted by the
chance of a collision).

On the other hand, it's still possible that a long-period comet or rogue
planet could come out of nowhere and wipe humanity out. Presumably the odds
are extremely remote, judging by the rarity of extinction-level events in the
geological record.

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cjensen
Goodness no!

An asteroid in an elliptical orbit, for example, could be a civilization
killer and might currently be undetectably far away right now.

We are missing a lot right now, and we need to spend money on much better
surveys.

~~~
jessriedel
You are at best disputing my terminology.

An object on such a highly eccentric orbit would be classified as a long-
period comet, which I mentioned. Yes, you can argue semantics about whether we
might still call such an object an "asteroid" if it had a certain composition
or primordial origin (which would be extremely unlikely for such an orbit).
But there is no sharp division between asteroid and comment composition (it's
a bimodal but smooth continuum) and this isn't relevant for the purposes of
tracking such objects.

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credit_guy
There are two families of asteroids in the asteroid belt, Alinda and Griqua,
which have quite eccentric orbits, and their orbits become more and more
eccentric as time passes. From time to time they come close to Mars (or other
interior planet), which slings them in a random direction. Some may end up
hitting us. That's how the Kirkwood gaps in the asteroid belt are formed.

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

~~~
jessriedel
Sure, but they aren't so eccentric as to evade detection because of having a
very long period.

