
Increasing Variety on Pluto's Close Approach Hemisphere and a Dark Pole on Charon - benbreen
http://www.nasa.gov/feature/new-from-nasas-new-horizons-increasing-variety-on-plutos-close-approach-hemisphere-and-a/
======
pmlamotte
This was linked in the article, but should anyone pass over it/not click
through, here is a regularly updated list of new pictures from the probe as it
gets closer: [http://pluto.jhuapl.edu/soc/Pluto-
Encounter/index.php](http://pluto.jhuapl.edu/soc/Pluto-Encounter/index.php)

I've been checking in every few weeks and it's been fun to see it slowly
getting clearer and larger. I recall watching shows about it on the Science
Channel when I was in high school and thinking 9.5 years would be so far away.
Feels odd that we're now only a few weeks away from it finally reaching Pluto.

~~~
kchoudhu
Wow -- the increase in resolution is wild.

1/25: [http://pluto.jhuapl.edu/soc/Pluto-
Encounter/data/pluto/level...](http://pluto.jhuapl.edu/soc/Pluto-
Encounter/data/pluto/level2/lor/jpeg/028445/lor_0284457178_0x630_sci_1.jpg)

6/25: [http://pluto.jhuapl.edu/soc/Pluto-
Encounter/data/pluto/level...](http://pluto.jhuapl.edu/soc/Pluto-
Encounter/data/pluto/level2/lor/jpeg/029751/lor_0297516568_0x630_sci_1.jpg)

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001spartan
This is so damn cool. It's humbling to realize the scale of the universe we
exist in, and how small a part of it we really are. And we're flinging probes
around the solar system, millions of miles away, to learn more about our
universe.

These are machines that still work, decades after they're launched on top of
the most powerful (and most violent) form of transportation we've created, and
after they travel millions of miles through the extremes that space provides.
It's awe inspiring that we can accomplish things like that, and it's
incredibly disappointing that more people don't realize the scale of what is
being accomplished.

~~~
fractaled
Speaking of scale, Pluto is more than 2.6 billion miles from Earth at closest
approach :).

~~~
iamcreasy
To put it into context, the closest distance between Earth and Mars is 33.9
million miles, and distance between Earth and Moon is only 238,900 miles.

~~~
yoha
This checks out. Closest theoretical approaches:

    
    
        >>> "%e" % (Pluto.orbit.periapsis - Earth.orbit.apoapsis)
        '4.272109e+12'
        >>> "%e" % (Mars.orbit.periapsis - Earth.orbit.apoapsis)
        '5.455552e+10'
        >>> "%e" % (Moon.orbit.periapsis)
        '3.631042e+08'
        >>> "%e" % Earth.radius
        '6.371000e+06'
    

Earth-Pluto: 4.27 Tm = 4.27e9 km = 2.65e9 miles

Earth-Mars: 54.6 Gm = 54.6e6 km = 33.9e6 miles

Earth-Moon: 363 Mm = 363e3 km = 226e3 miles

Earth radius: 6.37 Mm = 6.37e3 km = 3.96e3 miles

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cletus
I like many here find these space probes endlessly fascinating, for several
reasons. Of course there's the discovery aspect but what really intrigues me
are the engineering challenges and discovering things are huge problems that I
never thought of as being problems.

It's an incredible feat to have something like this operate for _decades_ (in
the case of Voyager and Pioneer) from both a hardware and software
perspective.

But as for eye-opening problems, two examples spring to mind.

Firstly, they don't know exactly where Pluto _is_. It was only discovered in
1930 and given it has an orbital period of 248 years, we haven't observed it
complete even half an orbit yet.

So it's visible to New Horizons but one thing they're not sure of is exactly
how far away it is. This is important because in the next week they need to do
a final course correction. More:

[http://www.nature.com/news/pluto-bound-probe-faces-its-
tough...](http://www.nature.com/news/pluto-bound-probe-faces-its-toughest-
task-finding-pluto-1.17811)

The second applies to the mission in planning phase to head back to Europa. I
knew Jupiter had a strong magnetic field but I didn't realize quite how
destructive it's radiation belts were and the source of them is actually
Jupiter's magnetic field capturing radiation from the Sun. This is why the
mission plans to do flybys rather than orbit Europa.

I think those of us who are software engineers can appreciate this on
typically a much smaller scale. Things often look much easier than they
actually are until you delve into the details. It's amusing to me to see this
apply on much grander scales too.

So it's going to be exciting to images from the flyby of both Pluto and
Charon. It's a shame the encounter will be so brief and the resolution of
Pluto not super-high (IIRC down to 20km or so) but it'll be a lot more than we
have now.

It makes me wonder how complicated an intercept course would've or could be to
really study Pluto.

Given our missions to Jupiter and Saturn in the last 20 years I wonder if
we'll see a return trip to Uranus or Neptune. I sure hope so.

~~~
tjl
Even if we don't know exactly where Pluto is, we do know enough about orbital
mechanics to have a very good idea of where it will be. Plus, they would run
simulations of the solar system to take into account the fluctuations due to
gravitational forces of the other planets.

Neptune has only completed one complete orbit since discovery. It was
discovered in September 1846 and has an orbital period of 164.8 years. So, it
would have completed an orbit in 2011.

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FranOntanaya
I'd love to see a simulation of particles moving around the Pluto Charon
system. I've always wondered how they behave near the barycenter.

Here's some clues about what could cause the variety:

[https://blogs.nasa.gov/mission-ames/2013/07/25/playing-
marbl...](https://blogs.nasa.gov/mission-ames/2013/07/25/playing-marbles-at-
pluto-looking-at-the-dynamic-dust-environment-generators-sweepers-and-sweet-
spots/)

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brianstorms
I've been firmly in the PLUTO IS A PLANET camp my whole life, and the 2006
decision to demote our distant neighbor to planetoid or worse I did not take
lightly.

But I have to admit, seeing how tiny the malformed rock is, smaller than the
United States, smaller than our own Moon, I have to revise my thinking.

But then . . . Pluto has its own moons! Impossible, but there they are. Five
known ones!

This is science at its best. Can't wait for the flyby.

~~~
fogleman
The center of mass of the Pluto / Charon system lies _outside_ of Pluto. So
Pluto is more like the larger body in a binary system.

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TTPrograms
It seems hard to say what they're really seeing there - deconvolution to the
extent they're doing can be incredibly fickle. You need to know your camera
nearly perfectly and have lots of SNR, to start. So it might be more likely
that the highly unusual dark region not previously observed is actually a
processing artifact.

Very interesting images nevertheless - we'll see how it bears out.

~~~
Osmium
> deconvolution to the extent they're doing

Do you have a link to share for more info on what exactly they're doing? (or
even some raw images next to some deconvolved ones?)

Regarding SNR, I believe these images are being sent lossless (whereas the
preliminary high-res images we're getting in a few weeks will be lossy for
now). Presumably they have a good profile of their camera from before launch
too, knowing that they'd have to do this. So I wouldn't be surprised if this
analysis does turn out to be accurate. Let's hope!

~~~
TTPrograms
The 3rd image in the original article compares the original and the
deconvolved result.

The main idea is you want to invert a linear transformation (a matrix) which
is given by the operation of your imaging system, i.e. a blurring operation.
This linear transform often has a poor condition number, however - this means
that you can't really invert it, or if you try to you end up with certain
components of your signal that need huge amplification, which makes noise
sensitivity a major issue.

One solution to this is to introduce a "prior" on your signal that represents
your expectations about what the signal looks like, i.e. is it smooth, or does
it have a few edges etc. Then you can better tolerate the inherent
sensitivities. I'm not sure what priors they're using for this situation or if
they're using any at all, so in the absence of such a description I'm taking
the results with a grain of salt.

See for example:
[http://people.seas.harvard.edu/~schan/deconvtv_folder/deconv...](http://people.seas.harvard.edu/~schan/deconvtv_folder/deconvtv_image.html)

------
fla
This is such an exiting period! New Horizons about to reach pluto, Dawn about
to reach Ceres, and Rosetta orbiting a comet approaching the sun.

~~~
dr_zoidberg
Dawn has been orbiting Ceres since March!

~~~
fla
Yes, that's right. I was under the impression that it's still getting closer.
Exciting nonetheless ;)

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iamcreasy
Does anybody know any dummies guide to astrophysics that explains how
scientists plan out the journey of the spacecraft with incredible precision?

~~~
abecedarius
If you'd like to try learning by doing, sort of, the 2009 ICFP Contest had you
write code to control a spacecraft performing several tasks:
[http://www.ittc.ku.edu/icfp-contest/](http://www.ittc.ku.edu/icfp-contest/)

I enjoyed it, though I don't think I got past the first couple of missions.
Can anyone recommend another game? There's Kerbal Space Program, which I
haven't tried but was said to stick to Kepler orbits, not like the
numerically-integrated gravity of the above simulation.

~~~
topynate
KSP is really good for exploring gravity assists, actually – they work just
the same way in the Keplerian 'patched conics' approximation as in real life.
For Newtonian physics, there's Orbiter, which is much more of a simulation
than a game; it puts you in our own Solar System, for one thing.

[http://orbit.medphys.ucl.ac.uk/](http://orbit.medphys.ucl.ac.uk/)

~~~
abecedarius
Neat, thanks!

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yk
So NASA can send a probe to Pluto, but can not show pictures and text without
resorting to Java Script. I believe this conclusively proves that HTML is not
rocket science.

~~~
sxcurry
Wow, the most amazing space venture in a very long time, over 9 years in
waiting, and you complain about JavaScript? I'm sorry, but I just don't
understand. I wouldn't care if the images were delivered to my house as a deck
of punched cards!

~~~
tizzdogg
I don't think it's possible for a thread to exist on hacker news without
somebody complaining about how the web page renders.

