Scientists think they’ve detected more plumes of water, shooting up from near Europa’s south pole. It’s early days, but we may have found a comparatively easy way to collect samples from the Jovian moon’s subsurface ocean.
Stephen Hawking says humanity needs to keep exploring space. I agree, although not quite for the reasons he gave.
SpaceX tested an engine they plan to use on their Mars transport, and Gaia’s data seems to have raised as many questions as it answers.
- Water Jets on Europa?
- Humanity’s Future: Looking Up
- Tech for the Earth-Mars Run
- An Expanding Universe: New Data, More questions
I’m cautiously optimistic about our future, partly because I know a bit about our past.
I don’t know why some folks associate ‘being religious’ with moping around, brooding on the futility of it all and acting as if their pet canary died.
I understand dragging through most days; feeling tired and guilty. Decades of undiagnosed major depression saw to that, and that’s another topic.
But we’re in a universe filled with wonders: a beautiful, ordered cosmos; unfolding in accord with physical laws which we are beginning to understand. (Catechism of the Catholic Church, 32)
No matter where we look, we can see “wonderful things.”1 The trick is learning to notice them.
Science and technology aren’t transgressions: they’re tools that we’re expected to use wisely. Being curious, studying the universe, is what we’re supposed to be doing. (Catechism, 35–36, 301, 303–306, 311, 1704, 2293–2296)
I keep saying this —
Thinking is not a sin. It’s faith and reason. We are rational creatures, and expected to use our brains. (“Fides et Ratio,” John Paul II (September 14, 1998); Catechism, 35, 32, 154–159, 299)
I’m focusing on humanity’s next few centuries today, but figure it won’t hurt to briefly review Earth’s last 252,000,000 years.
We still don’t know what caused the Permian-Triassic extinction event, or Great Dying, about a quarter-billion years back.
Earth’s gone through quite a few extinction events since then, but that’s the most drastic one we’ve discovered.
When it was over, up to 96% of all marine species were gone, along with 70% of terrestrial vertebrate species — and it’s the only known mass extinction of insects.
Not everything died, obviously. Scorpions showed up more than a hundred million years before the Great Dying. The last oversized Pulmonoscorpius had been dead for 94,700,000 years by then, but other scorpions were scuttling around, and still are.
Ancestors of today’s cockroaches survived, too. We’ve found 300,000,000-year-old cockroach wings in the Mazon Creek fossil_beds.
Scorpions, Cockroaches, Rats, and Us
The Great Dying wasn’t Earth’s first extinction event. The first we know of is the Oxygen Catastrophe, 2,300,000,000 years back, give or take.
That’s when cyanobacteria started dumping significant amounts of oxygen into Earth’s atmosphere: good news for us; lethally bad news for obligate anaerobes, critters that die when exposed to oxygen.
Another extinction event, about 201,300,000 years ago, killed off at least half of Earth’s species; which left room for dinosaurs.
Non-avian dinosaurs didn’t survive when something at least 10 kilometers across made the Chicxulub crater, 66,000,000 years back. That happened while eruptions were pouring a mile-deep-plus layer of lava where the Deccan Traps are today.
The Chicxulub and Boltysh impacts may have been nearly simultaneous, and Earth’s sea level was remarkably low. It was a really bad time to be living on Earth.
But life went on. Avian dinosaurs — ancestors of today’s birds — mammals, and ants, flourished. So, apparently, did mound-building termites — and, for a geologically brief time, Titanoboa and Gigantophis, oversized snakes.
Rats are newcomers, showing up somewhere between 6,000,000 and 3,5000,000 years back. Scientists are still working on the exact timetable, and that’s yet another topic.
Someone was making stone tools in humanity’s homeland 3,300,000 years ago. I talked about that last week. (September 23, 2016)
The point is that we’ve endured for upwards of three million years, including 2,580,000 years of the Quaternary glaciation, horrific plagues throughout Eurasia and part of Africa (165-180 AD and 1346-1350), and assorted disasters in other times and places.
I don’t think blind complacency makes sense, but I also think we’ll prove to be at least as durable as rats: and, given time, scorpions.
1. Water Jets on Europa?
(From NASA/ESA/W. Sparks (STScI)/USGS, via BBC News, used w/o permission.)
(“This composite image shows suspected plumes of water vapour erupting at the 7 o’clock position”
“Europa moon ‘spewing water jets’ ”
Jonathan Amos, BBC News (September 26, 2016)
“Further evidence has been obtained to show that Jupiter’s icy moon Europa throws jets of water out into space.
“Scientists first reported the behaviour in 2013 using the Hubble telescope, but have now made a follow-up sighting.
“It is significant because Europa, with its huge subsurface ocean of liquid water, is one of the most likely places to find microbial life beyond Earth.
“Flying through the jets with an instrumented spacecraft would be an effective way to test the possibility….”
We’re quite sure that there’s a large body of water, an ocean, under Europa’s crust and above the moon’s solid core.
The Galileo spacecraft’s instruments detected a significant magnetic field around Europa. The most reasonable explanation is that there’s a layer of highly conductive material inside the moon. The layer is almost certainly seawater.2
“Seawater” doesn’t guarantee “life,” but its presence makes life much more likely. Over the last few decades we’ve learned that life thrives around hydrothermal vents on Earth’s seabed, miles below the sunlit surface.2
Worth Another Look
Scientists at the Southwest Research Institute observed plumes over the same part of Europa in December 2012. Analyzing ultraviolet light from the area showed oxygen and hydrogen, most likely from water.
The 2012 observations, reported in 2013, and the ones released this week, tell scientists that there’s something interesting going on around Europa’s south pole — interesting enough to warrant another look.
One of our spacecraft, Juno, started settling into Jupiter orbit earlier this year. We’re getting good data and pictures from it, including the best look we’ve had to date of Jupiter’s poles. (September 9, 2016; July 29, 2016)
But Juno “has no life-detection equipment onboard,” as Jonathan Amos put it, and won’t be going close enough to Europa to collect samples. That will wait until later NASA and ESA missions.
(From NASA/JPL-Caltech/SETI Institute, used w/o permission.)
(“This reprojection of the official USGS Europa basemap is centered at the estimated source region for potential plumes … The black region near the south pole results from gaps in imaging coverage.”
“…Scientists may use the infrared vision of NASA’s James Webb Space Telescope, which is scheduled to launch in 2018, to confirm venting or plume activity on Europa. NASA also is formulating a mission to Europa with a payload that could confirm the presence of plumes and study them from close range during multiple flybys….”
(NASA press release (September 26, 2016))
Collecting and analyzing samples from those plumes will be tricky, partly because they’re intermittent: that’s assuming that they’re not some other sort of phenomenon. The latest observations picked them on three out of 10 occasions.
The 2012 observations only detected them when Europa was farthest from Jupiter, which may help mission planners.
Ice covering Europa’s subsurface ocean may be only a kilometer or so thick. Maybe. It looks like the ice is more like 10 to 30 kilometers, six to 19 miles, thick.2
That’s a lot of ice. Folks have developed pretty good drilling tech: including the Uralmash series rigs used at the Kola Superdeep Borehole. That project’s deepest borehole went down 12.262 kilometers, a tad over 7.6 miles. It’s still the deepest anyone’s drilled.
Developing an automated drilling rig that could go that deep or deeper in Europa’s granite-hard icy crust would be — challenging. Particularly if the idea was landing at Europa’s south pole, where it’s 50 K at the surface: -220 °C, -370 °F.
That’s cold enough to freeze oxygen at Earth’s sea level pressures.
In any case, sampling the plumes would sidestep the risk of contaminating whatever’s on, and in, Europa. If there is life there, I’m sure scientists would prefer being fairly certain that it didn’t arrive on an insufficiently-clean probe.
2. Humanity’s Future: Looking Up
(From Frank Augstein/AP, via Time, used w/o permission.)
(“Stephen Hawking strongly believes in the potential of commercial space travel, both for exploration and the preservation of humanity”
“Stephen Hawking Says The Human Race Has No Future If It Doesn’t Go To Space”
Kate Samuelson, Time (September 26, 2016)
“The physicist believes this world could be destroyed by nuclear war or a man-made virus
“When he was offered a seat on Richard Branson’s Virgin Galactic SpaceShipTwo vehicle, Stephen Hawking immediately said yes….
“…’I believe that life on Earth is at an ever-increasing risk of being wiped out by a disaster,’ Hawking writes, giving the examples of a sudden nuclear war or a genetically engineered virus.
” ‘I think the human race has no future if it doesn’t go to space. We need to inspire the next generation to become engaged in space and in science in general, to ask questions: What will we find when we go to space? Is there alien life, or are we alone? What will a sunset on Mars look like?’…”
I agree with Professor Hawking: humans need to keep asking questions, wondering what we will find over the next hill; or, these days, on the next planet. More accurately, I think we will keep asking questions: some of us, at least. It’s in our nature.
I don’t, quite, agree with the idea that we should be afraid of global catastrophe. Thoughtfully prudent, yes. Afraid, no.
The last I checked, we’re still not quite sure how strong emotions affect our decisions.3
My guess is that our “fear” responses work pretty well in situations like unexpectedly stepping on a badger — but not so much when making global policy decisions.
I’ve talked about environmental issues and what I think about dire predictions before. (August 12, 2016)
On the Move: 1,900,000 Years and Counting
Folks who look a bit like you and me showed up about 200,000 years back. Some did what folks have been doing for at least 1,900,000 years: going over the horizon and settling there, then repeating the process.
The current model met descendants of earlier explorers and colonists, most likely shocking the daylights out of neophobes by raising ‘mixed’ families, and were eventually living on every continent except Antarctica.
Make that living and raising families. Antarctica’s population is about 1,000 during winter, 4,000 during summer: technicians and scientists at research stations there, plus a few summer tourists. We haven’t “settled” Antarctica. Not yet.
Our most distant semi-permanent outpost so far is the International Space Station: in continuous operation since November 2, 2000. As I’ve said before, we’re curious, and move around. A lot.4
That may have helped ensure our survival.
Toba and the Next Planet
A volcano erupted where Lake Toba is today, 75,000 years ago — give or take 900 or so. The Sunda, Australian, and Burma plates are sliding past each other near there, so volcanic eruptions are fairly common.
The one 75,000 years back wasn’t the biggest ever. That’s arguably the Fish Canyon eruption, nearly 28 million years back now.
The Yellowstone hotspot is due for another big one “soon,” geologically speaking. The last eruption there was only 630,000 years ago, or thereabouts.
Where was I? Curiosity, being human, exploding mountains. Right.
The most recent big Toba eruption was — big. Whatever was living near the event disappeared under a pyrocaustic flow that covered about 20,000 square kilometers, 7,722 square miles.
Ash near the vent was up to 600 meters deep. There may have been survivors in parts of south Asia, but I suspect not many. Six meters of ash covered one place in southern India, and parts of Malaysia were nine meters deep in ash.
Folks who look sort of like me had learned how to make flint tools from Neanderthals by then, or maybe the other way around. My guess is that we learned burial customs from our Neanderthal cousins by then, although scientists are still debating that point.
There may or may not have been a “population bottleneck” at that point, with only 1,000 or so folks on Earth; which may or may not have been caused by the Toba eruption. What’s more certain is that south Asia was essentially depopulated.
That was then, this is now. Some of the folks who had been living east and west of the devastated area moved in. Today about 1,749,000,000 folks, a quarter of Earth’s population, are in south Asia.
If we’d all been there when Toba exploded: well, I’m glad we weren’t.
I don’t think another extinction event is imminent: but spreading out a bit more, as our technology allows it, couldn’t hurt.
Besides, I think quite a few of us are curious about what’s on the next planet.
3. Tech for the Earth-Mars Run
(From SpaceX, via BBC News, used w/o permission.)
(“The Raptor engine was fired at SpaceX’s test facility in McGregor, Texas”
“SpaceX ‘Mars’ rocket engine tested”
BBC News (September 26, 2016)
“Private firm SpaceX has carried out its first test of the Raptor rocket engine, designed to send humans to Mars.
“SpaceX founder Elon Musk announced that the engine had been fired at the company’s facility in McGregor, Texas.
“If his vision is realised, it could power a super-heavy launch vehicle that would transport people to the Red Planet in coming decades.
“But sending astronauts on round trips to our neighbour remains a formidable challenge….”
I strongly suspect that calling round trips to Mars “a formidable challenge” is an understatement.
We’ve learned quite a bit about building spaceships and space stations since 1951, when Harper & Brothers (I think that’s right) published Arthur C. Clarke’s “The Exploration of Space.”
We’ve also learned quite a bit about Mars: much of it discouraging.
Better telescopes helped scientists of the early 19th century learn more about Mars.
Schiaperelli’s canali were debatable and debated. Pierre Janssen, William Huggins, Hermann Carl Vogel, and Edward Walter Maunder, thought they’d detected water vapor in the Martian atmosphere.
“Because They Can”
A great many astronomers had noticed seasonal changes sweep across the planet’s surface.
The odds of finding life on Mars seemed pretty good — until 1965, when Mariner 4 sent back images of craters, detected no planetary magnetic field, and surface atmospheric pressure of 4.1 to 7.0 millibars, 410 to 700 pascals.
Earth’s atmospheric pressure at sea level is right around 101,325 pascals.
Orbiters found river channels and evidence that water once flowed on Mars. But that was a long, long time ago. Some water is still there, in the polar ice caps, and maybe deep underground.
Data from the Mars Odyssey orbiter shows that radiation on the Martian surface is about two and a half times higher than at the International Space Station. That’s not surprising, with the planet’s thin atmosphere and virtually nonexistent magnetic field.
Astronauts could visit Mars in the 2030s, if NASA’s plans hold up. Other nations have have plans for Mars: including India, whose Mangalyaan orbiter started surveying Mars September 24, 2014.
We’ll still be a long way, I think, from permanent Martian settlements.
But much of the tech developed for the first human missions should serve as prototypes for Martian habitat systems.
I think Jeffrey A. Hoffman and Elon Musk are right. The question isn’t if some of us move to Mars: it’s when we start.5
“These Are The 2 Big Hurdles To Setting Up A Mars Colony”
Jessica Orwig, Business Insider (January 15, 2015)
“Mars is a frozen wasteland devoid of life, liquid water, and breathable atmosphere. So why are companies like SpaceX and Mars One so bent on colonizing such unfriendly territory?
” ‘Human beings have always looked to expand the territory that we can live in,’ former NASA astronaut Jeffrey A. Hoffman told Business Insider. We spoke with Hoffman at BBC FUTURE’s World-Changing Ideas Summit about what it will take to colonize Mars. ‘You’ll find people who are willing to go and live there because they can.’…”
“Huge Mars Colony Eyed by SpaceX Founder”
Seeker.com (December 13, 2012)
“…He also estimated that of the eight billion humans that will be living on Earth by the time the colony is possible, perhaps one in 100,000 would be prepared to go. That equates to potentially 80,000 migrants….
“…’Some money has to be spent on establishing a base on Mars. It’s about getting the basic fundamentals in place,’ Musk said. ‘That was true of the English colonies [in the Americas]; it took a significant expense to get things started. But once there are regular Mars flights, you can get the cost down to half a million dollars for someone to move to Mars. Then I think there are enough people who would buy that to have it be a reasonable business case.’…”
4. An Expanding Universe: New Data, More questions
(From NASA/ESA, via BBC News, used w/o permission.)
(“Galaxy UGC 9391: We still have much to learn about the ‘dark’ components of the Universe”
“Gaia clocks speedy cosmic expansion”
Jonathan Amos, BBC News (September 23, 2016)
“Europe’s Gaia space telescope has been used to clock the expansion rate of the Universe and – once again – it has produced some head-scratching.
“The reason? The speed is faster than what one would expect from measurements of the cosmos shortly after the Big Bang.
“Some other telescopes have found this same problem, too.
“But Gaia’s contribution is particularly significant because the precision of its observations is unprecedented….”
I knew a Christian who said our sun goes around Earth, not the other way around, because ‘the Bible says so.’ He had a point, given a completely poetry-free reading of Joshua 10:12–13.
“The pillars of the earth” and “the mighty dome of heaven” are “Biblical,” too. But oddly enough, I’ve yet to meet a Christian who insists that we live under a big dome, on a flat plate supported by pillars. (1 Samuel 2:8; Job 9:6–7; Psalms 150:1)
Folks living around the Mediterranean’s east end thought of our home as flat at least 10 millennia back now. So did folks living in India, and that’s yet again another topic.
Somewhere between 26 and 24 centuries ago, Greek philosophers realized that their data made more sense if they assumed Earth was a sphere.
Aristotle gets credit for demonstrating that Earth is spherical, and a five-element theoretical model that held up until the 17th century, when Hennig Brand and Robert Boyle independently isolated phosphorus.
Quite a few folks in Europe were still reeling from the shock of discovering that Aristotle didn’t know everything, coming to conclusions which didn’t always make sense. I’ve talked about Albertus Magnus, Copernicus, and getting a grip, before. (July 29, 2016)
Around that time, Johannes Kepler came to the same conclusion that Thomas Digges had, back in the 1500s; and I’m getting ahead of myself.
Dark Sky Paradox and an Infinite Universe
On a clear night, folks can see lots of stars: and a whole lot more dark between stars.
That’s impossible: if stars are infinitely old, and distributed evenly through an infinite universe. No matter where we look, we’d be looking at the surface of a star.
Since there’s more dark than star in Earth’s night sky, there’s something wrong with that picture.
Olber’s paradox is named after Heinrich Wilhelm Matthias Olbers, who described the dark sky paradox in 1823.
I’d be surprised if the Lambda-CDM model of the Big Bang theory is the definitive, spot-on-accurate, final word in how this universe works; but right now it’s the best we’ve got.
Some physicists say what we’re observing at sub-atomic scales makes more sense if we assume that there’s more than one universe, and that’s still another topic.
A Cosmos Loaded with Puzzles
(From University of Virginia, via BBC News, used w/o permission.)
- “As the Earth goes around the Sun, relatively nearby stars appear to move against the ‘fixed’ stars that are even further away
- “Because we know the Sun-Earth distance, we can use the parallax angle to work out the distance to the target star
- “But such angles are very small – less than one arcsecond for the nearest stars, or 0.05% of the full Moon’s diameter
- “Gaia will make repeat observations to reduce measurement errors down to seven micro-arcseconds for the very brightest stars
- “Parallaxes are used to anchor other, more indirect techniques on the ‘ladder’ deployed to measure the most far-flung distances”
(Jonathan Amos, BBC News)
My hat’s off to Jonathan Amos for that explanation of how astronomers measure parallax. I talked about the first map from Gaia data two weeks ago. (September 16, 2016)
Where was I? Cosmology, Aristotle, parallax. Right. These scientists have been fine-tuning parallax measurements for Cepheid variables:
- “A test of Gaia Data Release 1 parallaxes: implications for the local distance scale”
Stefano Casertano, Adam G. Riess, Beatrice Bucciarelli, Mario G. Lattanzi; Astrophysics > Instrumentation and Methods for Astrophysics; Cornell University Library (Submitted September 16, 2016)
Cepheid variables are stars that pulse, which isn’t unusual by itself. Our star goes through an 11-year, or 22-year, cycle, depending on what you’re measuring.
Make that an approximately 11 or 22 year cycle. The cycles aren’t always the same length, there was the Maunder Minimum, and I’m wandering off-topic.
What makes Cepheid variable special is that they pulse very regularly, and the rate of their pulse is closely linked to their brightness. That makes them dandy for measuring distances. I put an unnecessarily-long link list near the end of this post.6
If these scientists are right, this universe isn’t 13,799,000,000 years old — plus or minus 21,000,000 years.
It may be 100,000,000 or so years younger.
That doesn’t affect my daily routine at all, but it’s important to scientists who are trying to work out exactly how fast this universe is expanding, why the rate of expansion seems to be increasing, and what’s powering the expansion.
What we know and can guess about dark matter, dark energy, and the rest of observable reality, is almost certainly nowhere near the complete picture.
It’s as if God created a cosmos loaded with puzzle games for us to solve.
- “ESA’s Gaia, HD 164695, and SETI”
(September 16, 2016)
- “Proxima Centauri b, Looking for Life”
(September 2, 2016)
- “Faith, the Universe, and Wisdom”
(August 28, 2016)
- “Earth Overshoot Day and Pollinators”
(August 12, 2016)
- “Studying Thousands of New Worlds”
(July 29, 2016)
1 On 26 November 1922, archeologist Howard Carter made a small hole in a sealed doorway and looked through, using a candle for illumination. His patron, Lord Carnarvon, asked “Can you see anything?” Carter replied — “Yes, wonderful things!”
2 Europa, Jupiter’s moon; Enceladus, Saturn’s moon; life; and science:
- Absorption spectroscopy
- Europa (moon)
- Extraterrestrial life
- Galileo (spacecraft)
- James Webb Space Telescope
- Juno (spacecraft)
- Tidal force
- Tidal heating
- NASA, JPL/NASA
- “NASA’s Hubble Spots Possible Water Plumes Erupting on Jupiter’s Moon Europa”
Karen Northon, NASA press release (September 28, 2016)
- Europa Mission
- “Hubble Space Telescope Sees Evidence of Water Vapor Venting off Jupiter Moon”
Joe Fohn, Southwest Research Institute press release (2013)
- “NASA’s Hubble Spots Possible Water Plumes Erupting on Jupiter’s Moon Europa”
- “How emotions affect logical reasoning: evidence from experiments with mood-manipulated participants, spider phobics, and people with exam anxiety”
Nadine Jung, Christina Wranke, Kai Hamburger, Markus Knauff; Frontiers in Psychology, via PMC/NIH (June 10, 2014)
- “Emotion, Decision Making and the Orbitofrontal Cortex”
Antoine Bechara, Hanna Damasio, Antonio R. Damasio; Oxford Journals (March 2000)
4 Being human, background and outlook:
- “Planetary Rover Developments Supporting Mars Exploration, Sample Return and Future Human-Robotic Colonization”
Paul S. Schenker, Terry L. Huntsberger, Paolo Pirjanian, Eric T. Baumgartner, Eddie Tunstel; Autonomous Robots (March 2003)
- “The Economic Viability of Mars Colonization”
Robert Zubrin, Journal of the British Interplanetary Society (1993)
- “Water extraction on Mars for an expanding human colony”
M. Ralphsa, B. Franzb, T. Bakerc, S. Howed; Life Sciences in Space Research (November 2015)
- “Mars Colony Will Have To Wait, Says NASA Scientists”
Matt Williams, Universe Today (May 11, 2016)
- “These Are The 2 Big Hurdles To Setting Up A Mars Colony”
Jessica Orwig, Business Insider (January 15, 2015)
6 More about measuring the universe:
- Frequently Asked Questions in Cosmology
Edward L. Wright; Astronomy & Astrophysics, UCLA Astronomy & Astrophysics, a division of the UCLA Physics & Astronomy Department
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