July 28, 2015 at 5:15 am #1588July 28, 2015 at 5:24 am #1589
Well, I just can’t resist saying Pluto is really, really cool.July 28, 2015 at 10:30 am #1590
I think in my mind I always pictured Pluto as a somewhat mishapen featureless blob. All I can say now is wow. Pluto is a real spherical world.July 28, 2015 at 3:51 pm #1606
Actually, if an object is of a certain mass, gravity will force it into a spherical shape. It’s no coincidence that all of the “real” planets and their larger moons are spherical whereas comets and asteroids are not.August 1, 2015 at 9:39 am #1916August 1, 2015 at 6:24 pm #1963
One unfortunate (and totally unavoidable) aspect of this mission is that about half of both Pluto and Charon remain unmapped in any detail.
Conceivably, another mission could be sent, timed so the other side of both bodies is facing the spacecraft near the time of closest approach. (If memory serves, the entire tidally locked Pluto Charon system rotates ever 6.4 days.) But what we’d really need is a Galileo or Cassini style mission that stops and stays a while, and such is very much unlikely. It was difficult enough to get this probe there at all, getting enough fuel out there WITH a probe for it to be able to hit the brakes is presently infeasible.
We launched the probe directly from Earth at 16+ kilometers per second. That’s the fastest direct launch we’ve ever done. Since we launched it in the direction of the earth’s orbital motion of about 30 km/sec, that was enough velocity to escape the sun. (Add 30 + 16 and you get 46 km/sec relative to the sun. We absolutely could not have done this mission any other way, our orbital motion gave us two thirds of what we needed, the one third we did supply was just barely possible to us.) The Jupiter boost was not actually necessary, but shaved a couple of years off the flight time, which meant that that was two years less time for something to break on the way to Pluto. I find this astounding in and of itself, since I was always hearing a couple of decades ago that we simply couldn’t get further than Jupiter without using something for gravitational assist. That’s still true for much heavier probes like Cassini. (Double the weight of the probe, double the weight of the entire rocket you need to start it on its way… and that’s why they begrudge every last gram of weight on the things. Consider how big that rocket is in relation to the payload.)
Hell, we haven’t even sent orbiters to Uranus and Neptune yet, and those are probably still much more interesting targets overall, now that we’ve seen Pluto as clearly as we have seen them. Our one mission to them was Voyager 2. Our one mission to Pluto was New Horizons. It will probably be a long time we revisit any of them, absent a major advance in space propulsion.
One trend that has shown up in our explorations is that those outer planets’ moons are really, really interesting, more so than we expected. Pluto is much like some of those moons… except for not orbiting a primary, and itself having moons, one of them big enough to really make it a double system, so we should not have been surprised to find some surprises!
August 7, 2015 at 1:46 am #2316August 7, 2015 at 1:56 am #2319
- This reply was modified 5 years, 8 months ago by SteveInCO.
Here’s a video showing the transit of the moon across the Earth. BTW, as dark as the moon looks against the Earth, we’re looking at the backside of the moon in full sunlight (just look at the Earth beyond it).August 7, 2015 at 2:52 am #2320
@-Davis, your link doesn’t animate for me. @-Unseen, there is a clearer and pithier animation here. (The video camera pointed at a screen went out of focus.)
I love it, even though it looks fake, at first. I still can’t figure out which layers are realtime vs composited. Stuff to notice: The sun’s light comes slightly by the left, as you can see some shadow on both earth and the moon’s eastern edges. Also, youtube commenters swear it’s faked because you can’t see the clouds move, but I do see some cloud changes, like in that storm system in the northern Pacific.August 7, 2015 at 2:59 am #2324
The truly appalling thing is that every comment on the YouTube page is written on the assumption that it’s a fake.August 11, 2015 at 2:09 pm #2544
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