What if?

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This topic contains 85 replies, has 15 voices, and was last updated by  Strega 5 years, 8 months ago.

Viewing 15 posts - 31 through 45 (of 86 total)
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  • #610

    Davis
    Moderator

    A colour composite with Chiron to scale (distance separating them not to scale). Pluto is a teeny weeny bit larger than thought and with each new image the amount of mysteries grow with giddy scientists speculating. What are the dark patches? Why is the polar region on Charon dark? Are there watery-icy layers below the surface? What about Pluto’s large hexagonal features? Why are there so many deep long scars on their surfaces? Why aren’t they balls of ice as our text books claimed? Artistry in their infinite creativity seems to be more widespread and beautiful than ever before.

    • This reply was modified 5 years, 9 months ago by  Davis.
    #643

    Davis
    Moderator

    New Horizon has already wizzed past Pluto. This is the last image sent to Earth before data silence began (it is actually a composite). It will be ten hours before processed data stars streaming in and several more before we get a crisp beautiful image.

    • This reply was modified 5 years, 9 months ago by  Davis.
    #653

    Strega
    Moderator

    @davis thanks for keeping us updated and filtering through images to bring these to us. Much appreciated and enjoyed πŸ™‚

    • This reply was modified 5 years, 9 months ago by  Strega.
    #677

    Unseen
    Participant

    From what I’ve seen, the most impressive thing is the quality of the photography. I haven’t seen any jaw dropping standing-in-need-of-scientific-explanation features. Some of the moons in the universe are far more amazing.

    Davis, you referred to the probe as a satellite. Is it actually a satellite (will it be in permanent orbit around Pluto?) or is it best described as a probe?

    #678

    Unseen
    Participant

    Unseen and seen. A contradiction in terms.

    #679

    Gregg R Thomas
    Participant

    I think it’s KOOL that some members of our little species have developed the ability to go out there and take pictures while the believers are still on their knees.

    #680

    Gregg R Thomas
    Participant

    Ha ha, number 7. How could you diss Unseen like that? He’s a legend.

    In his own mind. πŸ™‚

    #682

    Gregg R Thomas
    Participant

    OK, so if you were standing on Pluto looking at Charon and saw something walking around on the surface, aimed you 308 and fired, how long would it take for the bullet to get there and how much would you have to lead the target?

    #692

    SteveInCO
    Participant

    OK, so if you were standing on Pluto looking at Charon and saw something walking around on the surface, aimed you 308 and fired, how long would it take for the bullet to get there and how much would you have to lead the target?

    Answer, you can’t do it.

    http://nssdc.gsfc.nasa.gov/planetary/factsheet/plutofact.html

    The escape velocity of Pluto is 1.2 km/second which works out to a bit over 3900 feet per second. .308 ammo clocks in at 2700 fps or so. It will return to Pluto.

    OK that’s the easy answer. But is it possible that by shooting straight up, it will climb to the height of Charon before returning? OK, time to drag out the orbital mechanics books.

    2700 fps = .82296 km/sec.

    The circular orbital velocity is always 1/sqrt(2) times the escape velocity. So given an escape velocity of 1200 meters per second, circular velocity is 848 meters per second. In other words, if you fired a rifle where the bullet traveled at that speed, horizontally on the planet, it would skim along the surface and be in orbit (until it hit a hill somewhere). Now this is not much higher than the speed of .308. So let’s figure I am shooting a slightly more potent, specially loaded round that moves at 2782 feet per second (the same as 848 meters/sec).

    A circular orbit has a semi-major axis of whatever Pluto’s radius is. However, here’s another fact about orbital mechanics. If you are a given distance from the focus of the orbit, and moving at a certain speed, it doesn’t matter what direction you’re going, your orbit will have the same semi-major axis. It might be circular, a fat ellipse or an extremely narrow ellipse. And of course it might intersect the surface of the primary, which would mean it’s not really an orbit, but mathematically the part of the trajectory above the surface behaves like one.

    So firing that slightly hot .308 round at 2782 feet straight up gives you an *extremely* narrow ellipse with a semi major axis the same as Pluto’s radius. Given that the center of pluto has to be inside that ellipse, you can’t possibly get even that hot 308 round out to more than double the distance from Pluto’s center. Pluto’s radius is 1185 kilometers (according to that fact sheet), so that’s how far above the surface the bullet can go. Not enough to reach Charon.

    But it is kind of cool that a .308 round can go into orbit, if you fire it from the highest spot on the planet.

    • This reply was modified 5 years, 9 months ago by  SteveInCO.
    • This reply was modified 5 years, 9 months ago by  SteveInCO.
    #695

    SteveInCO
    Participant

    On a totally different note, I am still awestruck by the fact that, almost in my lifetime (certainly in my older brother’s lifetime) we have explored all eight of the other planets. Even if Pluto got demoted, it’s still a remarkable thing. My much younger self, astronomy head that I was back in the early 70s (before anything had even flown past Jupiter) would be gratified.

    #698

    SteveInCO
    Participant

    I’ve just seen reports that New Horizons has reported home. It survived the flyby, there was no errant piece of debris in the way.

    Now we get to spend sixteen months receiving copious amounts of data!

    #702

    SteveInCO
    Participant

    http://www.slashgear.com/weve-passed-pluto-where-are-the-photos-14392922/

    In particular, they updated a stamp the US issued quite some time ago.

    #706

    Unseen
    Participant

    A lot has happened in my lifetime. From the fallout of WW2 and music by Elvis to a close-up look at Pluto. And hopefully I have some time left.

    They say change has become more rapid than ever, but consider my grandmother. She was born into a world where people went to the next town on a horse-drawn buggy and took a shit in an outhouse. At night, their lighting consisted of candles and kerosene lamps. By the time she died, we could fly across the ocean in an airliner and had even walked on the moon.

    While they are hard to compare, I think the change she witnessed seems at least equal to the change I’ve witnessed.

    #711

    Davis
    Moderator

    Pluto survived the fly by was successful and new horizons survived the dust and debris around the system. A room full of Grey haired scientists who were only teenagers when the mission began are delighted. ? We are promised interesting press releases and images this evening.

    • This reply was modified 5 years, 9 months ago by  Davis.
    #713

    Davis
    Moderator

    @unseen it is not a satellite though for a brief time it was. Probe is better or perhaps someone here knows the best term.

    • This reply was modified 5 years, 9 months ago by  Davis.
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