New Horizons to flyby Pluto this year

[Ray McCarthy]

Nitrogen

Though why Pluto should have the amount of Nitrogen it appears to have (as well as frozen Methane), may be odd too.

 

[BAYLOR]

I wonder if the probe will find any standing water.

Pluto's over 3 Billion miles from the Sun. At that distance the surface temperature is about 300 or 400 below zero, there's no way you find any unfrozen water on the surface.

 

[Ray McCarthy]

300 or 400 below zero

You must be on Fahrenheit? Absolute Zero is a smidgen below -273 C
It sounds like a very cold place. That white Heart shape is likely colder than the dark Whale shape (assuming that's the part pointing at the sun). Though Pluto is rotating, I think it's poles / axis are pointing such that one side is mostly dark?

 

[BAYLOR]

You must be on Fahrenheit? Absolute Zero is a smidgen below -273 C
It sounds like a very cold place. That white Heart shape is likely colder than the dark Whale shape (assuming that's the part pointing at the sun). Though Pluto is rotating, I think it's poles / axis are pointing such that one side is mostly dark?

Now the big question , what's beyond Pluto? Another planet perhaps ?

 

[Ray McCarthy]

Lots of rocks, dwarf planets and comets.
Two families: Kuiper belt and Oort Cloud

If there is anything as larger than Pluto it must be far out. Lots of very small planets, but I don't think any have a prince and a rose.

In 1950, Dutch astronomer Jan Oort proposed that certain comets come from a vast, extremely distant, spherical shell of icy bodies surrounding the solar system. This giant swarm of objects is now named the Oort Cloud, occupying space at a distance between 5,000 and 100,000 astronomical units.

The Oort Cloud is a THOUSAND times further away than Pluto at it's furthest from the sun, when it's in the Kuiper belt

The Kuiper Belt is a disc-shaped region of icy objects beyond the orbit of Neptune -- billions of kilometres from our sun. Pluto and Eris are the best known of these icy worlds. There may be hundreds more of these ice dwarfs out there. The Kuiper Belt and even more distant Oort Cloud are believed to be the home of comets that orbit our sun. The best known resident of the Kuiper Belt is Pluto, but it also is home to Eris, Haumea, Makemake and countless comets.

http://solarsystem.nasa.gov/planets/profile.cfm?Object=KBOs

 

[Curt Chiarelli]

More coverage and Lovecraft Honoured.
http://www.theregister.co.uk/2015/07/15/pluto_hi_res_pictures_latest_new_horizons/

Not yet an official name I think.

This news brings a tear to my eye! Shall we petition N.A.S.A. to make it official? Anyone here agree with me?

 

[Ray McCarthy]

More surprises!
http://www.theregister.co.uk/2015/07/17/new_horizons_surface_of_pluto/

One thing is clear: Sputnik Planum is relatively young. The lack of craters (of which there are plenty in other areas of Pluto) indicates the surface was formed as little as 100 million years ago – and in fact, Moore posited, it could have been formed last week for all we know.
The plains have also revealed a series of features that look like wind-driven deposits. Moore speculated that they were complex hydrocarbons that had fallen from the sky and been blown into cervices on Pluto's surface, noting that similar features exist on Earth.
The mountains to the south of Sputnik Planum have now been named the Norgay Mountains, in honor of Tenzing Norgay, the first Sherpa to reach the summit of Everest. It's the first time any feature in the Solar System has been named after a Nepalese citizen, Stern said.
"I'm still having to remind myself to take deep breaths," he said. "This landscape is astoundingly amazing."

The first surprise is that the dwarf planet's atmosphere extends much further from the surface than first thought – about 1,000 miles, to be exact. The upper part is nitrogen, with a lower band of methane and a thin band of complex hydrocarbons close to the surface.

 

[hardsciencefanagain]

Thanks,Ray.Can't be more up-to-date than this,I suppose.
Good pix,BTW

 

[Serendipity]

And the latest results / analysis that has come out shows that Pluto is shedding nitrogen atmosphere at the rate of 500 tons per hour, enough to produce a solar shock wave in the Solar wind... see http://gizmodo.com/plutos-atmosphere-is-billowing-away-into-space-1718582990

 

[kythe]

The biggest surprise to me was that Pluto has an atmosphere at all. I thought atmosphere was related to gravity - the size of the object determines its ability to pull in lighter gasses. Mercury and our moon are also small, and neither have an atmosphere, yet Pluto does.

 

[Venusian Broon]

The biggest surprise to me was that Pluto has an atmosphere at all. I thought atmosphere was related to gravity - the size of the object determines its ability to pull in lighter gasses. Mercury and our moon are also small, and neither have an atmosphere, yet Pluto does.

On a first guess - Mercury and the Moon are much hotter, being relatively close to the sun - so they will have been baking for billions of years and will have lost much volatile material (higher temp = higher average kinetic speeds of gas molecules = greater chance of these molecules finding escape velocity). Also the effect of the solar wind will be much stronger closer in - which easily strips away atmospheres if they are not protected with magnetic fields.

 

[Mirannan]

Lots of rocks, dwarf planets and comets.
Two families: Kuiper belt and Oort Cloud

If there is anything as larger than Pluto it must be far out. Lots of very small planets, but I don't think any have a prince and a rose.

The Oort Cloud is a THOUSAND times further away than Pluto at it's furthest from the sun, when it's in the Kuiper belt

http://solarsystem.nasa.gov/planets/profile.cfm?Object=KBOs

There is at least one object (Eris) beyond Neptune which is larger than Pluto, although for some technical reason it isn't classed as being in the Kuiper Belt.

Given that there is very little light way out there, and that the Kuiper Belt is a very big place, I think it easily possible that some currently undiscovered object in the Kuiper belt is larger than Pluto.

For similar reasons, it's also possible (though less likely) that there is an undiscovered ice giant out there, maybe at 100AU or so. It's not even beyond the bounds of possibility that there is a brown, or VERY feeble red, dwarf orbiting somewhere between the Kuiper and the Oort Cloud.

To demonstrate the possibility, Alpha Centauri has a red dwarf companion (Proxima) which is an M5.5 and 900+ AU from the A star. It's quite possible that an unnoticed M8 or M9 dwarf is hiding way out there. The limit appears to be around 2000AU for a binary star.

 

[Ray McCarthy]

I think we would see the gravitational effect of a brown or red dwarf, which would have to be many times more massive than Jupiter.
Eris was thought to be larger than Pluto till New Horizons enabled better measurement. It's still thought to be 27% more massive, but is actually smaller.

Eris is 2,326 ± 12 kilometres. In July New Horizons caused size of Pluto to be upgraded to 2,370 km! Thus Pluto is less dense than expected.

I'm sure there are lots of exciting things to be found in the Kuiper belt and Oort Cloud. New Horizons may even discover something. It's still got a mission.

Eris and Dysnomia(its one known moon) are currently the most distant known natural objects in the Solar System apart from Comets.

Future Mission objectives of New Horizons after the Pluto flyby listed on Wikipedia.

Because the flight path is determined by the Pluto flyby, with only minimal hydrazine remaining [rocket fuel], objects need to be found within a cone, extending from Pluto, of less than a degree's width, and within 55 AU. Beyond 55 AU, the communications link will become too weak [to report to Earth].

 

[Mirannan]

Ray - I stand corrected. This does bring into play the issue of just what "largest" means. Mass or volume? Incidentally, this is an issue for an awful lot more objects. Up to their maximum mass, white dwarf stars get smaller the more massive they are. I'm not quite so certain of it, but believe the same is true of neutron stars. And, of course, any red giant is immensely larger in volume than any main sequence star.

 

[Ray McCarthy]

Well till July, i.e. only some days ago as I write, they thought Eris was larger diameter and greater mass. Larger is usually volume. Visual. A kilo of Aluminium is "larger" than a kilo of Lead.

Stars are a lot odder than planets. But even Iron compresses. I believe the Earth's iron core is denser than iron in the crust. There are basically three classes of planets. The Gas Giants compress the most. But even the "rocky" planets like Earth compress as they are larger.

But stars compress far more with size than a gas giant. Hence a star x3 the mass of our sun might "burn" very much faster, maybe up to 9x faster. So will not be as long lived.

Neutron stars are the most dense thing not a black hole. I don't know if they vary in density like regular stars, possibly not as much as the range of possible masses is much less (only about 2:1 variation in mass observed)?

I think beyond about x3 solar masses they become black holes. One about the same mass as the sun is only about 12km diameter! Thus density is about 300,000,000,000,000 x that of the sun.


EDIT:

Some neutron stars rotate very rapidly (up to 716 times a second, or approximately 43,000 revolutions per minute) and emit beams of electromagnetic radiation as Pulsars. Indeed, the discovery of pulsars in 1967 first suggested that neutron stars exist. Gamma-ray bursts may be produced from rapidly rotating, high-mass stars that collapse to form a neutron star, or from the merger of binary neutron stars. There are thought to be on the order of 10^8 neutron stars in the galaxy, but they can only be easily detected in certain instances, such as if they are a pulsar or part of a binary system. Non-rotating and non-accreting neutron stars are virtually undetectable

https://en.wikipedia.org/wiki/Neutron_Star

The Pulsars are a kind of Galactic "GPS". They can even be used today to navigate in our own Solar System.

 

[Dave]

Have you heard of the Titus-Bode Law? Before Pluto was discovered it was enthusiastically used to predict that there would be a big planet out beyond Neptune and I remember Patrick Moore still being quite keen on it in the 1970's. The oddness of the Pluto-Charon system doesn't necessarily discredit the Law completely (since there is no theory of a causal effect for it in any case, it is just a mathematical curiousity) and because there probably still is some very large planet out there that we haven't discovered. It works in other planetary systems we have recently discovered, and all it means in our own is that some very strange but cataclysmic event happened out there. Don't forget that also well as having a smaller orbit than the Law predicts, Neptune also spins very, very fast, and has a satellite, Triton, that orbits in the opposite direction of Neptune's axis of rotation.

 

[Vertigo]

The presence of Pluto was first predicted based on tiny perturbations in Uranus' orbit:

In the 1840s, Urbain Le Verrier used Newtonian mechanics to predict the position of the then-undiscovered planet Neptune after analysing perturbations in the orbit of Uranus.[27] Subsequent observations of Neptune in the late 19th century led astronomers to speculate that Uranus's orbit was being disturbed by another planet besides Neptune.

This would suggest that the possibility of finding anything truly massive out there is very slim. If perturbations of the orbit of Uranus caused by the tiny mass of Pluto (smaller and much less massive than our moon, remember) can be detected then I can't see anything truly massive being out there without our being able to detect its effect on our known planets. Certainly not something like a red dwarf.

 

[Serendipity]

The presence of Pluto was first predicted based on tiny perturbations in Uranus' orbit:



This would suggest that the possibility of finding anything truly massive out there is very slim. If perturbations of the orbit of Uranus caused by the tiny mass of Pluto (smaller and much less massive than our moon, remember) can be detected then I can't see anything truly massive being out there without our being able to detect its effect on our known planets. Certainly not something like a red dwarf.

We know that a red dwarf star, Scholz’s star, passed through our Solar System 70,000 years ago (and this was only discovered in the last year or so). In other words the mass was there, but has moved on. As to how it perturbed the Solar System, others with the necessary computation tools would be able to tell you better than me.

 

[Venusian Broon]

We know that a red dwarf star, Scholz’s star, passed through our Solar System 70,000 years ago (and this was only discovered in the last year or so). In other words the mass was there, but has moved on. As to how it perturbed the Solar System, others with the necessary computation tools would be able to tell you better than me.

Yeah we discussed it a little bit here on the forums: https://www.sffchronicles.com/threads/551561/

The thing that stuck in my mind about the article was how little it had seemed to have affected anything. i.e. they'd run simulations and no perturbations and there was no strange anomalies in the real data that might be explained by it

The only reason they knew about it was they had more accurately determined its trajectory in the local area and worked out it must have brushed by at that time.

 

[hardsciencefanagain]

Summarizing from the work of Mamajek,Burgasser and Kniazev:
If W0720* experienced occasional flares similar to those of the active M8 star SDSS J022116.84+194020.4 , then
the star may have been rarely visible** with the naked eye from Earth for minutes or hours during the flare events. Hence, while the binary system was too dim to see with the naked eye in its quiescent state during its flyby of the solar system 70 kya, flares by the M9.5 primary may have provided visible short-lived transients visible to our ancestors.
*Scholz's Star
**V(isibility) around 6
For comparison, flybys this close (0.25 pc)are statistically rare (2.4%) among encounters by all
stellar systems that penetrate the Sun's tidal radius of1.35 pc of which 4.5 occur per Myr

intriguing
PS:
Simulations byFeng & Bailer-Jones (2014) suggest that encounters with gamma
< 105:3 are unlikely to generate an enhancement in the distribution of longitudes for long-period cometscompared to that predicted to be generated by Galactic
tidal effects. All of the 104 simulated orbits had gamma <107:0, hence the pass of the W0720 system should havea negligible statistical impact on the ux of long-period comets during the coming millenia.
Gamma is the parameter:encounter induced flux of Oort Cloud comets
(vide)Feng, F. & Bailer-Jones, C. A. L. 2014, Monthly Notices of the
Royal Astronomical Society, 442, 3653