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Old 17th July 2015, 00:30   #46
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Re: Pluto, at last! A historic day for space exploration

Thank you for all your kind replies! Its so great to see that space-stuff still excites many.

Just a few images have come back,and it has left scientists scratching their heads and ready to throw their current theories into the dustbin.

Pluto turned out to be absolutely nothing like they imagined!

Pluto, at last! A historic day for space exploration-15152plutonewhorizonshighresolution20150714ifv.jpg

Pluto is extremely cold. Situated at the far reaches of the Solar System,it doesn't get as much heat from the Sun,as does Earth. The Solar flux decreases double for every single unit of distance. Hence,these distant icy bodies were thought to have formed around cores of rocks which got clumped together while the Solar System was forming and then got covered with ice.

But its not ice as we know,because the surface temperature of Pluto is around -220 Celsius! So its not only too cold for water-ice but the surface is actually made of solid nitrogen. And clumps of solid methane.

So its a planet covered with nitrogen ice.

Pluto, at last! A historic day for space exploration-tvhhzjq.jpg

Now since Pluto's orbit is very eccentric,ie,its not perfectly circular(it comes closer to the Sun than Neptune during a part of orbit),it was theorized that a part of that surface nitrogen would sublime and rise up to become a tenous atmosphere,and would freeze and solidify as it goes farther away from the Sun.

So as far predicting Pluto's surface geology,it was thought to be quite ancient and covered with craters. Craters are a great sign of an ancient surface because that indicates the lack of any surface weathering or active geological process to erode them. Greater the crater count,more old the surface.

Ancient cratered surface of the dark side of the moon.
Pluto, at last! A historic day for space exploration-back_side_of_the_moon_as163021.jpg

The Pluto,from that picture,has totally stumped scientists. As you can see,there is not a single sign of a crater.

Instead what you can see are those giant icy mountains. Those mountains are said to be 3-4 kms tall,jutting straight out of the surface. What a sight it must be if anyone is standing on the surface and looking up at it.

And beside the mountains you can see a flat plain which looks like it has been created out of a liquid flow. And you can see some canyons,cliffs and escarpments surrounding it. This shows that it is a very geological active world. And the scientists are pretty flummoxed as to what is causing it. Bear in mind that when people say its geologically active,these features are said to be not more than 100 million years old,which in planetary geology is like yesterday.

Our planet has something which has yet not been found on any other planetary body as of yet and that is active tectonic plates. The radioactive decay of the core of our planet gives off tremendous amounts of heat and energy which keeps the crust very active. The plates move out about,clashing with each other,getting consumed back into the Earth at the subduction zones and is constantly replenished and kept active. Thats why the surface of the Earth is so young and it creates mountains,canyons,continents and keeps weathering processes like the water cycle going on.

A smoothed crater in the Martian desert
Pluto, at last! A historic day for space exploration-victoria_crater_from_hirise.jpg

Other planets also have interesting and active geology but not on the level of Earth. Surface of rocky planets like Mars is very old and is not troubled much by its thin atmosphere. Its core far cooler than Earth to allow tectonics. Venus,although it is a hellish place thanks to its incredibly dense atmosphere,it has no active tectonics to keep on shaping its land.

Sand Dunes on Mars.
Pluto, at last! A historic day for space exploration-esp_027864_2295.jpg

The outer moons though are surprisingly active.

Volcano erupting on left.
Pluto, at last! A historic day for space exploration-800pxpia01081color_mosaic_and_active_volcanic_plumes_on_io.jpg

There is the Jupiter's volcanic moon Io(Mustafar from Star Wars).It has probably more volcanoes than earth and it spews out molten sulfur 500km up in the air.

Pluto, at last! A historic day for space exploration-europainterior1.jpg

Jupiter's moon Europa,which is said to consist of a planet encircling liquid water ocean underneath its frozen surface.

Largest sea on Titan,called 'Kraken Mare'
Pluto, at last! A historic day for space exploration-titanmethanerivernetworksmap.jpg

There is Saturn's rockstar moon called Titan,which is like a mini-Earth.It has a thick atmosphere,it has something analogous to our water cycle but since it is very cold so the water is replaced by methane. There are methane clouds,it rains methane and there are lakes and seas on Titan.

Geyser's of Enceladus
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And Saturn's moon Enceladus,which has these huge rows of water geysers which throws water straight into space.This water is said to come from an underground ocean like Europa and gets heated and comes out on the surface.

Young surface of Enceladus
Pluto, at last! A historic day for space exploration-saturnmoonhotsprings.jpg

These moons dont have a radioactive core to supply them heat,so how come they have such active meteorology? The answer is the Gas Giants they orbit around. Jupiter and Saturn exert immense gravitational forces on their moons. The forces are so strong that they kind off pull and push on these moons,a rhythmic stretching and squeezing. These forces give rise to something called 'Tidal Heating'. And it is this tidal heating that allows water to exist in liquid form under the surface and also keeps the surface young.

Pluto, at last! A historic day for space exploration-tidal_bulges.jpg

But Pluto doesnt orbit a gas giant.Although it has an extremely large moon called Charon,relative to its own size,Charon is not large enough to cause tidal heating.So scientists are not sure what is keeping Pluto's surface active.

Much to learn.

BTW a splendid picture of Charon has come too.

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Look at that deep cut on the top right-side,where you literally look through and see the other side. Its said to be a few kms deep.

PS: Excuse me for any scientific inaccuracies.I am just writing what i know from mucking around in space related stuff whenever i can.Please do look up wiki and other places to get a more accurate picture.
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Old 17th July 2015, 01:10   #47
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Re: Pluto, at last! A historic day for space exploration

Beautiful write up. If you were my science teacher, I would never bunk the classes. Thank you for sharing this awesome piece of knowledge.
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Old 17th July 2015, 13:06   #48
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Re: Pluto, at last! A historic day for space exploration

Avishar, it's seems to be you are the new horizon sent by Team -Bhp to Pluto . No need to go any further after reading your posts. No need for gathering information on TV , Internet etc, etc. What a thread !!!!!!!!!!!
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Old 17th July 2015, 14:58   #49
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Re: Pluto, at last! A historic day for space exploration

Quote:
Originally Posted by avishar View Post
Its amazing that the cost of New Horizons will not even cover a cost of a new missile development, but funds for space are hard to find (and for war much easier).
That line. Must be the definition of the human race. We probably need to be spending more on space exploration....but probably we will...when we have no other choice!

Thank you for a very nice thread. And this is why I love movies like Interstellar.
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Old 17th July 2015, 15:02   #50
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Re: Pluto, at last! A historic day for space exploration

Wow, what an absolutely brilliantly written write up! Your knowledge on the subject is just astonishing, thank you so much for enlightening us with all these nuggets of knowledge.
I, for one, am definitely going to remain glued to this thread for more and more updates. Given my limited knowledge on the subject, i probably won't contribute as much though!
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Old 17th July 2015, 20:08   #51
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Re: Pluto, at last! A historic day for space exploration

Wow this read has lead me to more reading and more reading and more, so much so that I actually forgot that I skipped my lunch. Excellent information and write up, gives me goosebumps.
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Old 17th July 2015, 20:44   #52
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Re: Pluto, at last! A historic day for space exploration

Avishar, please continue with this update as more data and photos come in. Please write some more about the moons of Jupiter and Saturn too - they seem to be most interesting heavenly bodies. Your simple precise style of writing makes this most interesting to read. look forward to more photos.
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Old 18th July 2015, 01:07   #53
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Re: Pluto, at last! A historic day for space exploration

Thanks a lot Avishar, for taking the trouble to make this thread and post all this information. I love astronomy and closely follow all the developments re orbiters and spacecraft going near astronomical objects. Your thread was a pleasure to read and set me off on a wikipedia hunt for several hours !
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Old 18th July 2015, 08:24   #54
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Re: Pluto, at last! A historic day for space exploration

Excellent thread Avishar!

I never knew why Pluto was demoted, now I know!

Rated the thread a very well deserved 5 stars!
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Old 18th July 2015, 09:58   #55
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Re: Pluto, at last! A historic day for space exploration

Excellent write up and exposition. I wish we had an active Thanks option on this thread. You must have spent a lot of time researching all the information - if I may say so the namesake of Micky Mouse's dog!
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Old 18th July 2015, 11:36   #56
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Re: Pluto, at last! A historic day for space exploration

Avishar,

Fascinating and a must read thread. As a child I watched Star Trek the TV series and Star Wars the movie which made me into a space tech, astronomy and sci-fi buff.

There's no thanks button in the Shifting Gears section but please accept my thanks for having spent so much time and effort to share this knowledge with us.
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Old 18th July 2015, 12:28   #57
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Re: Pluto, at last! A historic day for space exploration

Some more updates in National Geographic:
http://news.nationalgeographic.com/2...t&sf11085665=1



Quote:
Originally Posted by chandrda View Post
1. In layman terms how does the satellite know where it is
2. How does it precisely go up to certain KMS from a planet and then take a turn etc
Missions are carefully planned. The whole flight path is simulated on a computer. Simulation takes all forces into account, such as the power the internal engines produce or the gravitational tugs of all significant objects along the way. The onboard computer is then programmed to fire the right engine with right amount of power, so that the machine stays in its path.

But sometimes, some unknown design flaws or unforeseen forces may play a part in the machine drifting from its flight path. For example, read about Pioneer Anomaly. Then, some course correcting measures have to be taken remotely from earth to get the machine back in its path.

Quote:
3. How do they avoid all the other asteroids, stars zooming around in space.
The satellite is of the size of a grand piano. The asteriods in the asteriod belt are so far away from each other than even the earth can probably go through the asteriod belt without a single asteriod crashing into it. Obviously I am exaggerating, as I am not taking earth's gravity into account while making this statement
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Old 21st July 2015, 15:59   #58
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Re: Pluto, at last! A historic day for space exploration

"The Telegraph" has just reported a picture of our Earth shot from one million miles away by a camera on Nasa's Deep Space Climate Observatory (DSCOVR).

This is the first view of the entire sunlit side of Earth.
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Old 22nd July 2015, 07:17   #59
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I would not have read science with so much enthusiasm in school. Very interesting to read about Wikimedia article on Pioneer Anomaly.
Wonder how many such miniscule forces need to be accounted for in calculating the orbit trajectory. While reading about this many more links came up including Cassini Anomaly. Now will read that up.
Thanks again for starting this thread.
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Old 22nd July 2015, 08:34   #60
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Re: Pluto, at last! A historic day for space exploration

Very informative and concise write-up. Since this is an outer space related thread, I would recommend everyone to experience the VR app 'Titans of Space' using your Google Cardboard headset. It's really an immersive experience.

P.S: I'm not associated with the app team in anyway. Just sharing my experience.
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