New Horizons

[xXIndestructibleEVAXx]

So I never knew Pluto had an atmosphere before... why didn't I know that?

(Or does it? I've heard it in four or five different sources...)

It has a periodic atmosphere of methane and nitrogen IIRC, that freezes and falls at periapsis and evaporates at apoapsis.

[Frida Space]

It has a periodic atmosphere of methane and nitrogen IIRC, that freezes and falls at periapsis and evaporates at apoapsis.

We don't yet know that for sure. Pluto's atmosphere was discovered in the late '80s by the Kuiper Airborne Observatory (SOFIA's predecessor) looking at an occultation event, so we haven't seen it change during an entire orbit. It is thought that some/all of it might freeze as it recedes from the Sun, but we can't prove it yet. Plus, because of thermal lag, even now that Pluto has already reached periapsis and is heading towards its apoapsis, its atmosphere hasn't started to freeze yet.

The only components we know of are N2, CH4, and CO, but some Ar is expected, and the methane photochemistry will naturally lead to many higher hydrocarbons (e.g., acetylene, diacetylene) and nitriles (e.g., hydrogen cyanide, dicyanoacetylene).

Its current surface pressure is expected to be around 10-20 microbars (10-20 million times lower than Earth's)

Edited June 30, 2015 by Frida Space

[grawl]

Pluto is more and more interesting.

It seems to be way more than a dull rock in space.

IF (let's supputate ) it's a crater, how old do you reckon it could be ? Charon formation ?

I feel like I'm looking at an history book about the solar system when I watch these photos

[Frida Space]

IF (let's supputate ) it's a crater, how old do you reckon it could be ? Charon formation ?

Obviously it's too early to speculate, but given Pluto and Charon's tidal lock, they should both lack tidal heating, and so they should be pretty inactive bodies at least from a tectonic/geological point of view. That would make me think that Pluto's surface should be fairly old, but will all that sublimation action going on between atmosphere and surface (which scientists believe could even lead to some "sublimation winds"), and also the exchange of dust between Pluto and its moons (I read a paper on that recently), I doubt its surface is actually too old.

[Frida Space]

Methane detected!

[lajoswinkler]

What could that huge dark area be?

It almost makes me want to say it's the birthplace of Charon.

[Frida Space]

What could that huge dark area be?

It reminds me of the equatorial dark areas on Triton. Very interesting.

- - - Updated - - -

I'll post them here too, in case anyone missed the link to the NASA press release I published before.

This is the methane (in pink) detection. The image was obtained via Ralph's MVIC's methane filter. They chose to go with the methane instead of the green filter, which is making taking true color pictures a bit difficult, so we better appreciate it

And this is the solar flux as measured by the Alice spectrograph on June 16th. A few hours after encounter, Alice will observe two occultations: Pluto-Sun at 12:51:25 UTC and Charon-Sun at 14:17:41 to study their atmospheres.

[Frida Space]

It's confirmed, all is clear on New Horizons's path. The spacecraft won't need a further last-minute TCM and will use its main flyby trajectory (and not a backup one).

[Frida Space]

Plus, this image showing the differences between two sets of 48 combined 10-second exposures taken at 8:40 and 10:25 UTC (105-minute interval) on June 26th, from 21.5 mln km away. Only Pluto, Charon, Nix, Hydra, Kerberos, Styx and a few stars and errors which the software has mistakenly left are visible. No danger on New Horizons' path!

Also, check out these cool LORRI-MVIC (Ralph) color images of Pluto and Charon. Unluckily, those evenly-space, 300-wide equatorial dark patches are on the opposite hemisphere, the one that will set over the horizon 3 days prior to closest encounter and, from New Horizons' perspective, never come back.

[grawl]

Also, check out these cool LORRI-MVIC (Ralph) color images of Pluto and Charon. Unluckily, those evenly-space, 300-wide equatorial dark patches are on the opposite hemisphere, the one that will set over the horizon 3 days prior to closest encounter and, from New Horizons' perspective, never come back.

That's sad.

Now we will have to bear with the "dark side of Pluto" theorists

[lajoswinkler]

Oh, that's very unfortunate. :/

[Kryten]

They will attempt to image the opposite hemisphere using reflected light from Charon, but from what I've heard they aren't too optimistic with what results they expect from that.

[justidutch]

That's sad.

Now we will have to bear with the "dark side of Pluto" theorists

On the bright side (pun intended), we might get a new Pink Floyd album?!

[Frida Space]

They will attempt to image the opposite hemisphere using reflected light from Charon, but from what I've heard they aren't too optimistic with what results they expect from that.

Yea, we shouldn't be expecting too much. Think about photographing Earth's night hemisphere using only moonlight. Now think of doing the same with a thousandth of the incoming light.

[lajoswinkler]

And going that fast.

[LordFerret]

Plus, this image showing the differences between two sets of 48 combined 10-second exposures taken at 8:40 and 10:25 UTC (105-minute interval) on June 26th, from 21.5 mln km away. Only Pluto, Charon, Nix, Hydra, Kerberos, Styx and a few stars and errors which the software has mistakenly left are visible. No danger on New Horizons' path!

http://www.nasa.gov/sites/default/files/thumbnails/image/15-143.jpg

Also, check out these cool LORRI-MVIC (Ralph) color images of Pluto and Charon. Unluckily, those evenly-space, 300-wide equatorial dark patches are on the opposite hemisphere, the one that will set over the horizon 3 days prior to closest encounter and, from New Horizons' perspective, never come back.

http://www.nasa.gov/sites/default/files/thumbnails/image/nh-7-1-15_pluto_charon_color_hemispheres_annotated_jhuapl_nasa_swri.jpg

In looking at the image on the right, I notice that each of those dark spots has a corresponding light spot above it ... same with the image on the left, the long dark swath having a light swath immediately above it. I'm thinking 'shadow'.

[Frida Space]

Getting real close now...

[Beduino]

Also, check out these cool LORRI-MVIC (Ralph) color images of Pluto and Charon. Unluckily, those evenly-space, 300-wide equatorial dark patches are on the opposite hemisphere, the one that will set over the horizon 3 days prior to closest encounter and, from New Horizons' perspective, never come back.

http://www.nasa.gov/sites/default/files/thumbnails/image/nh-7-1-15_pluto_charon_color_hemispheres_annotated_jhuapl_nasa_swri.jpg

That looks quite a bit like Duna and Ike.

[Starwhip]

Getting real close now...

http://1.bp.blogspot.com/-Yu7RFbLuaa0/VZZiBIkG8XI/AAAAAAAAEus/JWRB07cs1UQ/s1600/dan.PNG

What is exciting is that it's still a week's worth of flight time away.

[tygoo7]

Getting real close now...

http://1.bp.blogspot.com/-Yu7RFbLuaa0/VZZiBIkG8XI/AAAAAAAAEus/JWRB07cs1UQ/s1600/dan.PNG

That looks very cool! Can't wait for the better detailed pictures!

[peadar1987]

That looks very cool! Can't wait for the better detailed pictures!

Every single picture coming back is the most detailed picture of Pluto/Charon ever taken. How cool is that?!

[Frida Space]

Taken June 23rd-29th, from 24-18 mln km.

This animation shows how the LORRI photos, like the ones above, were colored: first, you take the LORRI high-res map (left), then you combine it with a lower-res map of the colors of Pluto by Ralph/MVIC (right) to produce a high res approx. true color image (center).

[Scotius]

It's noticeably getting bigger Awesome and exciting at the same time.

[Aanker]

Those white spots/areas... Clouds?

[Streetwind]

Unlikely. Probably just patches of ice.