Before the New Horizons mission, we knew Pluto was very cold, had little or no atmosphere, and that was about it. (October 30, 2015; July 10, 2015)Now scientists think they've spotted 'ice volcanoes' on Pluto that look a lot like shield volcanoes on Earth and Mars.
New Horizons headed for 2014 MU69: for a flyby in January, 2019. And that's another topic.
(From NASA/APL/Southwest Research Institute, used w/o permission.)
(New Horizons position at 2200 UTC/1600 Central Standard Time. (CDT) (November 12, 2015))
Using Our Brains
Earth isn't flat, poetry isn't science, and curiosity isn't a sin. There, I've said it. Again. Repeatedly. (July 24, 2015; March 29, 2015)Briefly — we're rational creatures, created in the image of God, and "little less than a god." Studying this universe, and using that knowledge is part of our job. So is using our power responsibly. (Genesis 1:26-27, 2:7; Psalms 8:6; Catechism of the Catholic Church, 35-36, 282-289, , 355-373, 1704, 2292-2295, 2402, 2415-2418, 2456)
"Little less than a god" isn't God. Forgetting that gets us in trouble. (June 19, 2015; March 29, 2015)
We're supposed to use our brains. Thinking is not a sin. (Wisdom 7:17; Catechism, 35, 159, 1730-1738)
I run into folks whose attitude toward science and (new) technology is ambivalent, at best. I figure Job 5:6-7 is right that "...man himself begets mischief, as sparks fly upward."
As Thomas Aquinas said, blaming our tools doesn't make sense. (June 12, 2015)
1. Ice Volcanoes on Pluto: Maybe
(From NASA/JPL-JHU/SWRI, via BBC News, used w/o permission.)
("Wright Mons is located south of Sputnik Planum on Pluto"
(BBC News))
"New Horizons: Pluto may have ice volcanoes"
Jonathan Amos, BBC News (November 9, 2015)
"Two possible ice volcanoes have been identified on the surface of Pluto.
"They are seen in images returned from the New Horizons probe, which flew past the distant dwarf planet in July.
"The mountains are several km high and tens of km across, and each has what appears to be a depression in the top.
"Unlike Earth volcanoes that spew molten rock, Pluto's volcanoes - if that is what they are - would likely erupt an icy slush of substances such as water, nitrogen, ammonia or methane....
"...if cryo-volcanism can be established, it would be an immensely exciting discovery.
"While the phenomenon has been postulated to occur on several outer Solar System bodies, nothing really convincing has been detected; certainly not in terms of mountain-building.
"The two candidates at Pluto are found just south of Sputnik Planum, the smooth plain on the planet's equator.
"They have been informally called Wright Mons and Piccard Mons...."
(From NASA/JPL-JHU/SWRI, via BBC News, used w/o permission.)
("Piccard Mons (L) and Wright Mons (R): The colours denote height. Blue is low; brown is high; green is intermediate in height"
(BBC News))
We're getting a look at a bigger fraction of the planet's surface than we did in Mariner 4's flyby of Mars. I'm pretty sure scientists will want a Pluto orbiter for follow-up observations. (October 30, 2015)
Meanwhile, there's a great deal of data to work with — about 20% of the total stored on New Horizons. The first "Pluto journal paper" came out last month. I'm quite sure that many more will follow:
- "New Horizons: First Pluto journal paper discusses dwarf planet's origins"
Jonathan Amos, BBC News (October 15, 2015)
Pluto's cup-capped mountains look a lot like Earth's shield volcanoes, and similar structures on Mars.Olympus Mons, the tallest known mountain in the Solar System — that's a composite image from the Viking 1 orbiter (June 22, 1978) — is almost certainly a shield volcano, like Earth's Hawaiian islands, but on a larger scale.
Landers haven't explored Olympus Mons yet, so we don't have core samples: but I'm reasonable sure that it's made of basalt, like its counterparts on Earth.
As our probes began sending back reports from other worlds, we found volcanoes on Mars, Venus, and Mercury.
Volcanoes on the Solar System's other inner planets are like Earth's: formed when liquid rock comes to the surface and freezes. Beyond our star's asteroid belt, it's a different story.
Two of Jupiter's moons have cryovolcanoes: volcanoes with cold 'lava.' Io's volcanoes are mostly liquid sulfur. Volcanoes on Enchiladas have 'lava' made of water mixed with nitrogen, methane, carbon dioxide, and other substances.
Saturn's moon Titan may or may not have cryovolcanoes, but under all those clouds, it's hard to tell.
Triton's 'lava' is water and ammonia, with nitrogen gas mixed in at least occasionally. Voyager 2 observed nitrogen gas and dust geysers during its 1989 flyby of Neptune. The geysers were all between 50° and 57°S, close to Triton's subsolar point.
Comparing Voyager 2's observations of Triton with data we're getting about Pluto from New Horizons should tell us more about both worlds. Pluto is made of roughly the same stuff as Triton, and is about the same size.
If you haven't read enough about Pluto and Triton yet, there's more:
- "At Pluto, New Horizons Finds Geology of All Ages, Possible Ice Volcanoes, Insight into Planetary Origins"
Dwayne Brown / Laurie Cantillo, NASA; Mike Buckley, Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland; Maria Stothoff Southwest Research Institute, San Antonio; via jhuapl.edu (November 9, 2015) - "Powering Triton's recent geological activity by obliquity tides: Implications for Pluto geology"
F. Nimmo, J. R. Spencer; Icarus, Volume 246; via adsabs.harvard.edu (January 2015)
(Abstract) - "Triton"
Voyager, the Interstellar Mission, NASA/Jet Propulsion Laboratory; via webcitation.org (last updated October 18, 2010) - "Heat flow and depth to a possible internal ocean on Triton"
Javier Ruiz, Icarus; via Science Direct (December 2003)
2. Background: Why Counting Craters Matters
(From NASA/JHUAPL/SwRI, used w/o permission.)
("This portrait of Pluto is in enhanced color, to illustrate differences in the composition and texture of Pluto's surface."
(NASA))
"The Impact of Craters"
Kelsi Singer, New Horizons science team, NASA (October 13, 2015)
"Hello! It's Kelsi Singer again from the New Horizons science team to talk about one of my favorite planetary geologic features –impact craters. They may just look like holes in the ground, but amazingly, craters can give us all sorts of useful clues to a planet's history....
"...A surface with more craters indicates that it's older, geologically, than a less-cratered surface. Pluto displays many good examples of this concept. Any guesses as to which parts of Pluto mission scientists think are younger?
"If you went with the informally named Sputnik Planum – the left half of Pluto's 'heart' feature – as a young geologic unit, then you are on the right track. So far we have not identified any obvious craters on Sputnik Planum. We can also try to put an actual date on a surface (e.g., that a given surface is 1 billion years old), but this is more difficult because it requires some knowledge of how often impactors (chunks of space debris) of a certain size hit the surface to make craters.
"Age-dating based on craters is complicated by a number of other factors as well. I will highlight one big issue here: How one 'sees' craters is affected by lighting over the planet's surface. Just like on Earth, the lighting on Pluto and Charon changes both with latitude and over the course of the day. When the sun is directly overhead, there are very few shadows cast and it is hard to see topography, but that overhead lighting makes it much easier to see dark or bright markings. The opposite is true when the sun hits the surface at a shallow angle near sunrise or sunset: topography is easy to see, but bright and dark colorations are often washed out...."
(From SwRI/Kelsi Singer, via NASA, used w/o permission.)
("These close-up images of Pluto and Charon illustrate the effect of lighting geometry on the appearance of craters."
(NASA))
Those names may change. I talked about Pluto, names, and donuts, before. (July 24, 2015)
I like 'backgrounders' like this NASA post: your experience may vary.
A big difference between Earth and Earth's moon is how many craters each has. More accurately, how many craters are easily-seen.
Some lunar craters are fairly young, like North Ray crater: the result of an impact some 50,000,000 years back. That's "young," in geological terms; particularly for worlds like our moon, where there's not much in the way of atmosphere or plate tectonics.
Much of our moon's surface looks pretty much like it did when North Ray crater formed.
Earth's another story. Our planet has some obvious meteor craters, like Meteor Crater. It's been called Canyon Diablo Crater, and scientists call it Barringer Crater: honoring Daniel Barringer, who demonstrated that it was a meteor crater.
But visible meteor craters are so rare on Earth that calling it "Meteor Crater" makes sense: there aren't many like it, and none nearby.
Meteor Crater is about 50,000 years old. Since then, erosion has taken from 15 to 20 meters from the rim and added about 30 meters to the basin.
At that rate, there won't be much left in 50,000,000 years.
Planning Ahead
(From Christopher R. Scotese, Paleomap Project, used w/o permission.)
Meanwhile, if Earth's crust keeps moving at today's rates, in about 50,000,000 years the Mediterranean will be a mountain range, the Atlantic will be considerably wider, and Antarctica won't be quite so neatly positioned over the south pole.
There isn't much we can do about plate tectonics, not yet, but we've begun getting ready for the next asteroid headed for Earth.
Mountains have been falling out of the sky at odd intervals since Earth formed, and life recovered each time. Now that we're here, though, preventing the next extinction-level event seems prudent.
America's Congress consigned "H.R. 5587 (111th): To establish a United States Commission on Planetary Defense, and for other purposes" to committee limbo, but I think there's a chance that we won't have a replay of the Worcester incident on a global scale. (January 16, 2015)
For one thing, the United States isn't the only outfit with tech needed for space operations.
The last I heard, Reaction Engines Limited's Skylon was still in development, SpaceX may work the bugs out of its reusable launch vehicle, and many of the folks who worked on the defunded McDonnell Douglas DC-X project should still be around.Meanwhile, Planetary Resources may have found a way around treaties that prohibit non-science/government activity in space. (May 8, 2015; January 16, 2015; October 3, 2014)
On a more positive note, India's Mangalyaan Mars orbiter, and NASA's decision to get commercial long-distance service for Mars, are — I think — hopeful signs that someone will get the job done. (October 10, 2014; August 1, 2014)
And that's yet another topic. Topics
More about Pluto and being human:
- "Kerberos, Mars: Answers Raise New Questions"
(October 30, 2015)
Particularly - "Pluto, Earth 2.0, and Life in the Universe"
(July 31, 2015)
Particularly - "New Horizons: Past Pluto, Outward Bound"
(July 17, 2015)
Particularly - "Climate Change, Deccan Traps: Still Learning"
(May 8, 2015)
Particularly - "Setting Earth's Thermostat"
(February 20, 2015)
Particularly
No comments:
Post a Comment