
A Hole in Mars - jamesbritt
http://apod.nasa.gov/apod/ap120718.html
======
avar
I clicked the "speculation" link thinking it would be a forum thread full of
scientist debating whether it was caused by volcanism or something similar, I
didn't expect to be trolled by APOD.

~~~
axx
i don't get why they do that?

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mkr-hn
Scientists are some of the world's greatest comedians.

~~~
mcguire
Well, that's one way of putting it.

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ChuckMcM
It looks remarkably like a sinkhole. Although one could joke, "Hey guys we
found your Mars Climate Explorer!"

Given the fact that its on the side of a volcano it could also be a hole in a
lava tube. But whatever it is, it is _really_ cool and damn wouldn't it be
nice to have someone there we could ask to roll over and check it out?

~~~
stephengillie
I agree, a 115ft (35m) wide, 65ft (20m) deep sinkhole.

How far away is this from the Mars Rovers? Even having another perspective to
see this would be amazing!

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vilhelm_s
I think roughly 4200km from Spirit and 6400km from Opportunity:

[http://toolserver.org/~geohack/geohack.php?pagename=Pavonis_...](http://toolserver.org/~geohack/geohack.php?pagename=Pavonis_Mons&params=0.8_N_246.6_E_globe:mars_type:mountain)

[http://toolserver.org/~geohack/geohack.php?pagename=Spirit_r...](http://toolserver.org/~geohack/geohack.php?pagename=Spirit_rover&params=14.5718_S_175.4785_E_globe:mars_type:landmark)

[http://toolserver.org/~geohack/geohack.php?pagename=Opportun...](http://toolserver.org/~geohack/geohack.php?pagename=Opportunity_rover&params=1.95_S_354.47_E_globe:mars_type:landmark)

The rovers have driven 8km and 35km respectively, so this is out of reach. :)

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joshuahedlund
How far is it from the projected landing site of Curiosity?

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gautier
At 6480 km, this is even further away and clearly out of reach.

[http://en.wikipedia.org/wiki/Mars_Science_Laboratory#Landing...](http://en.wikipedia.org/wiki/Mars_Science_Laboratory#Landing_site)

[http://toolserver.org/~geohack/geohack.php?pagename=List_of_...](http://toolserver.org/~geohack/geohack.php?pagename=List_of_craters_on_Mars:_A-G&params=5.5_S_222.3_W_globe:mars_type:landmark&title=Gale)

~~~
ChuckMcM
Road trip!

~~~
skeletonjelly
Coming this summer!

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xefer
We have a pretty creepy looking one here on Earth too:

[https://maps.google.com/maps?ll=61.279143,-73.66333&spn=...](https://maps.google.com/maps?ll=61.279143,-73.66333&spn=0.143038,0.308647&t=k&om=1&z=12)

~~~
antoko
Pretty cool, not quite the same, since we know what it is.

But thanks for making me spend the rest of my afternoon wikipediaing around on
random geological occurrences.

<http://en.wikipedia.org/wiki/Pingualuit_crater>

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miguelrey
I love that Pingualuit crater was formerly called "Chubb Crater"

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shmerl
I didn't really get why he proposed to call it Chubb crater. Chubb didn't
discover it or anything.

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nrbafna
10 lines of CSS makes this site slightly more pleasant to the eyes :-)

<http://i.minus.com/i0i1hE5frYO4T.png>

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CamperBob2
(Shrug) The image got smaller and the text got blurrier, but maybe my eyes
aren't the best optimization targets.

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wlesieutre
Your browser probably shrunk the image he linked so that it fit. Try clicking
for full size.

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phon
Perhaps this feature or one like it could be incorporated in to a future
colony by sealing up the hole and artificially stabilizing the interior
structure? I know similar ideas have been floated in the past for the
conversion of lunar lava tubes into habitable space.

<https://en.wikipedia.org/wiki/Lunar_lava_tube>

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yesbabyyes
It's obviously the dwelling of a Sarlacc.

~~~
axx
Even though this is an awesome topic, i must say, i laughed!

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mirkules
In lieu of Curiosity landing on Mars in just two weeks, I wonder if one of
these is within reach for the rover to do some exploration? Although it's
probably too dangerous and the rover is probably not equipped to explore
something like this.

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asadotzler
The chances of this being within single digit kms of the Opportunity rover are
very very slim. Mars is a big planet. The MERs are amazing, and have outdone
all expectations, but they're not magical.

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mirkules
Yeah, I figured it would be slim, but I'm guilty of letting my imagination run
away from me. Btw, what's an MER - Mars Exploration Rover? Agreed, if yes: I
wish I was more into Astronomy when Opportunity and Spirit landed, but
thankfully, they lasted long enough for me to appreciate the feat, while in
progress.

~~~
asadotzler
Yep. MER is Mars Exploration Rover.

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ComputerGuru
If an exploration vehicle were to go there and check it out, how difficult or
impossible would it be for it to leave afterwards?

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skeletonjelly
Relevant XKCD: <http://www.xkcd.com/695/>

By leave you mean, exit from inside the hole? Leave the perimeter?

~~~
ComputerGuru
Exit from within the crater.

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tbrownaw
Looks a bit similar to
[https://www.google.com/search?q=bb+hole+in+glass&tbm=isc...](https://www.google.com/search?q=bb+hole+in+glass&tbm=isch)

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D_Alex
Could we put a glass roof over that and fill the interior with a breathable
atmosphere?

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kkovacs
We europeans were aware of this since our childhood. :) Where had they thought
Der Maus lives?

<http://www.youtube.com/watch?v=-ROKq_WXFA8>

(Die Abendteuer der Maus auf dem Mars - The adventures of the mouse on the
Mars)

~~~
hkolek
actually the correct article for the nominative of "Maus" is "die", in the
title "Die Abenteuer der Maus" "der Maus" is genitive so that's why it stands
with "der" but the correct nominative is "die Maus" ("Maus" is feminine). Also
note that "Abenteuer" has nothing to do with "Abend" (evening) so there's no
"d" in it. SCNR.

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phreeza
Are the links in the APODs always this humorous?

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truxs
Well, they previously talked about water on mars
<http://apod.nasa.gov/apod/ap050401.html>

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htf
"Holes such as this are of particular interest because their interior caves
are relatively protected from the harsh surface of Mars, making them
relatively good candidates to contain Martian life"

Isn't that grasping at straws a little? I'm not a biologist, but it seems
highly unlikely to me that life would develop in a hole 35 meters across.

~~~
swombat
Life wouldn't develop there, but if life used to cover the surface of Mars,
and largely died over time, but was still surviving in some places, this would
be one of the likely spots.

~~~
htf
I see. It still sounds like a long shot though for life to survive for a long
time in such a small space.

~~~
adventureful
The caves and small places of Earth say otherwise. So do the intense
environments on Earth that we've found life in. It's at least as plausible
that life can hang on, sheltered in the smallest of places, as it can anywhere
else. Micro organics often don't mind if you put them in a small place, with
little sunlight, high or low heat, high or low oxygen, etc.

The biggest problem would be if the changes Mars underwent were too
fundamentally anti-life for anything to survive whether it was in a cave or
anywhere else.

In my opinion, we're going to find out on Mars that there are forms of
microbes that can hang on in sedentary 'ready' state for a billion years, in
extreme environments, just waiting to jump back to activity. Most of Mars will
be barren, but there will be small pockets of microbes (most likely in a
sheltered cave, under ice, or similar) in a form of extreme suspended
animation.

------
Rotor
This is fascinating, especially whether the hole was created from a top impact
or from the bottom such as volcanic eruption.

On another note, why are we discovering this just now? I was under the amateur
impression that the entire surface of Mars was scanned and imaged by NASA at
some point. But again, I may have interpreted that incorrectly.

~~~
Arelius
> why are we discovering this just now? I was under the amateur impression
> that the entire surface of Mars was scanned and imaged by NASA at some
> point.

It's easy to forget just how large Mars is, as a comparison, if we scaled Mars
up to the size of Earth, the hole would only end up being about 120 meters, or
about %30 larger than an American football field. And when it's a feature that
we pretty much need human eyes on to determine it's significance, it's easy to
imagine how we've missed it. Just imagine trying to find a random football
field sized thing in Google Earth, somewhere on the planet.

And to make the comparison even more valid, Mars isn't covered in water, and
has a very comparable amount of land surface area as Earth does. in that case,
it makes the hole only about 36 meters when scaled up to the surface are of
Earth, which is likely what you'd be searching for in Google Earth.

Not to mention that I have no idea to what resolution Mars was scanned and
imaged at, considering imagery I see of Earth often, the mentioned scans could
easily have pixels larger then the entire size of that feature.

Hence it's easy to imagine that many more interesting features of similar size
exist on the martian surface, sitting there in plain view, waiting to be
discovered.

~~~
swombat
It's pretty high-contrast, though. Presumably an algorithm could find
interesting high-contrast, high-symmetry structures quite easily...

~~~
ojilles
This image is probably not the resolution all of Mars got imaged at, right?

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Arelius
I don't have the tools on this CPU to get good numbers, but if that hole is
about 35 Meters, I'd estimate to resolution to be about 20 CM/Pixel. I know
it's often difficult to find civilian access to Imagery at a better resolution
than 5 M/Pixel for some places on Earth.

It's probably safe to assume we don't have imagery this good for the entire
surface of Mars.

Edit: It seems likely that these new images are captured with this equipment:
<http://en.wikipedia.org/wiki/HiRISE>

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vladocar
Strange few days ago I made this free Android App that takes info from APOD
and NASA
[https://play.google.com/store/apps/details?id=nasa.project.v...](https://play.google.com/store/apps/details?id=nasa.project.vladocar)
and today we have unusual picture of Mars on HN.

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jnw2
If we had one of the surplus Hubble-diameter Naval Reconnaissance Office
mirrors orbiting Mars with a suitable camera, would we have better pictures
than this?

And could one of those mirrors be mounted in the trunk of a SpaceX Dragon
spacecraft?

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ostarr
Has anyone ever spent any time over at: <http://marsanomalyresearch.com/> ?
Thoughts?

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marknutter
Sounds like the opening to a pretty cool scifi movie.

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internetcitizen
Why isn't it red?

~~~
macey
Pretty sure Mars looks red because of the atmosphere. The surface isn't
actually red. Could be wrong.

~~~
artursapek
I think you are.
[https://www.youtube.com/watch?v=4YQBuuhh76A&feature=play...](https://www.youtube.com/watch?v=4YQBuuhh76A&feature=player_detailpage#t=127s)

~~~
iuguy
I think you're underselling the video. That is a fascinating presentation on
aerial mars exploration.

~~~
artursapek
It was linked to elsewhere in this thread. I'm just citing it to answer this
one misconception.

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rapind
I think it's pretty obvious what this is.

<http://imgur.com/Ei4r0>

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enraged_camel
A meteorite could have crashed through a thinner portion of the surface and
created the hole.

~~~
ChuckMcM
Actually, because it is circular the chance of it being a meteorite is slim.
This is because the ejecta of a meteor crater is related to the angle at which
the meteor hits, the more oblique the angle, the more oval the crater. A
circular crater would suggest a perpendicular collision. That would suggest a
very slow or very fast meteor, the latter would have caused a bigger crater.
The third challenge with the meteor hypothesis is that the 'hole' suggests a
cavern, and the cavern would have undergone a lot of compressive stress when
struck. One would have to figure out how the meteor went through the top of
the cavern without collapsing it (the shock wave from the impact would have
pushed all along the top).

So its not impossible that it was a meteorite but it is improbable.

~~~
runjake
You sound convincing, but then I look at high resolution pictures [1] of the
Moon and have my doubts. I don't think those are sinkholes.

That said, it does look like a sinkhole in this case.

1\.
[http://www.nasa.gov/centers/goddard/images/content/238403mai...](http://www.nasa.gov/centers/goddard/images/content/238403main_moon.jpg)

~~~
ChuckMcM
To be clear, I wouldn't rule _out_ a meteorite, I'm just saying that in order
for it to be a meteorite some things need to be understood. The sinkhole
hypothesis fits the picture precisely, but requires that someone explain how
the top of the cavern got opened in the first place.

In a traditional research setting the next thing we would be doing is coming
up with ideas that would rule out a hypothesis in order to give us higher
confidence in the ones that remain. To that end, you've added data which
doesn't help us rule out either of our hypotheses so it doesn't advance us
toward our goal of understanding.

Finding a circular meteor crater on the moon with a cavern underneath it would
be useful.

Another useful thing is to look at the sides of the hole. If the material was
removed by pushing outwards, the sides will have one shape, if it was removed
by 'draining' into the hole in the center they will have another shape. A good
experiment you could run on earth to think about that would be a put some sand
over a hole and drain it, take that shape. And then to take the same setup,
cover the hole lightly, and blow on it with a directed stream of air until you
punch through the thin covering on the hole and then take that shape.

If we can figure out the probable way in which the material was removed, that
too can inform our hypothesis. I encourage you to keep coming up with ways to
figure this out.

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mmaunder
Wormsign?

~~~
AsylumWarden
Vacant Sarlacc pit?

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indiecore
I wonder how we'd explore it. I guess land a probe with a transmitting station
near it and have a rover on a wire go fall in?

~~~
stephengillie
Could we get a flying drone down there?

What does it take to make flight happen on Mars? The air is thinner, so would
more force be required for airplanes and helicopters to fly? How well would
hot-air or helium inflatables work, compared to Earth?

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jameyc
X-Plane had some interesting observations about the physics of flying on mars
a few years back.

<http://www.x-plane.com/adventures/mars.html>

~~~
bitwize
Wow, that's gotta be one of the most pumped things I've ever read.

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adv0r
I don't really understand how come no-one was able to see it before... I don't
know how it works, but since telescopes are looking for stars and stuff much
more distant that mars, I was confident that they scanned the whole surface of
neighbors planets decades ago... Some explanation?

~~~
MiguelHudnandez
Things that could cause it to be missed:

* Angle of photography

* Time of day (direction of sunlight)

* Weather conditions

We often ignore problems that are "closer" to us. For example, the oceans on
our own planet are still very much a mystery, yet we still look outward.

~~~
mistawobin
What specifically about our oceans are a mystery?

~~~
R_Edward
I'm just going to leave this right here. <http://www.xkcd.com/1040/> It's a
little bit of awesome.

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tejaswiy
I'm not usually the one to complain, but really? Not just front page, but #1
of HN?

~~~
lifeisstillgood
From submission guidelines:

    
    
      anything that gratifies one's intellectual curiosity
    

I just spent a whole day in AES encryption, specifications and code. Being
reminded there is a wider world out there, quite literally, is fine by me,
especially a world where the answers are not obvious or wrapped in politics -
why is the surface white? Is it impact or collapse?

Edit - just neatened up

~~~
tejaswiy
Yes, yes, I know the guidelines and I agree with you ofcourse. I'm not against
discussing non CS / Startup related topics. I just felt that this particular
topic isn't interesting enough for whole of HN to rank it at #1.

I also realize the absurdity of complaining about a topic that doesn't match
my interest in a news aggregator, but oh well.

~~~
lifeisstillgood
I suspect you might be, like me, beginning to suffer from deja-HN

I think I would like to capture the opinions of HN's best discussions,
categorise them and then be able to filter on - oh look another discussion on
web security best practises. Fine - does it add anything beyond what we
already have filed under best-of-HN-security - no? Ok ignore.

It's what I suspect kills most forums, not really going downhill, but going
round and round the same hill.

Instead of some of our more prolific members saying "I have posted on this
before (a lot)" maybe they could say "look at the HNBrain on
#dontdropyourdayrate "

Cheers

