European officials seem to think that planning about what to do when an asteroid heads their way is a good idea. I think they're right.A SpaceX cargo run to the International Space Station arrived on time, but the flight's experimental reusable booster didn't land properly. Actually, it crashed.
I started writing about asteroid impacts, which reminded me of ice ages, dodos, and responsibility. This isn't the most tightly-organized post I've ever done.
Asteroids, Ice Ages, and Us
(Image © Don Davis; from PAINTINGS at www.donaldedavis.com)
Something about 10 kilometers, 6.2 miles, across fell out of the sky roughly 66,000,000 years back. Scorpions, cockroaches, many avian dinosaurs, and quite a few other species, survived: including many mammals.
But when the Cretaceous-Paleogene extinction event was over, about a quarter of Earth's species had died out. It wasn't the biggest extinction event ever, or the smallest.
The most recent, or the most recent two, are the Quaternary and Holocene extinction events. They started 640,000, 74,000, and 13,000, and 10,000 years ago years ago.
Conventional wisdom is that extinction events had natural causes up to 10,000 years back: and that everything since then is our fault. I'll get back to that.
Scientists are still learning about Earth's long history: extinction events included.
We're pretty sure that sometimes a nearby supernova kills off a noticeable number of species, sometimes a whole lot of volcanoes are erupting around the same time, and then there are Earth's on-again/off-again ice ages.
The current ice age, the Quaternary glaciation, started about 2,580,000 years ago. (July 11, 2014)
The last I heard, scientists weren't sure whether we're at the end of the Quaternary glaciation, or in one of this ice age's periodic warm spells.
In my youth, serious thinkers were in anguish over the coming ice age. More recently, global warming has been the doom awaiting us: and at the moment, we're supposed to be upset about "climate change."
I don't doubt that Earth's climate is changing. It's been changing for about 4,540,000,000 years — so far. I think it'd be very odd if it stopped changing in my lifetime.
Remember the Walghvogel
The dodo is a poster child of man's inhumanity to bird. Heedless of their peril, I've read, the innocent dodos of Mauritius fell before the relentless onslaught of vicious club-wielding sailors.It makes a good story.
Scientists have suggested that the walghvogel — Dutch for tasteless/insipid/sickly-bird, and an early name for the dodo — died out because dogs, pigs, cats, rats, and crab-eating macaques, ate their eggs.
Those who like to writhe in agony over the evils of man may find solace in the thought that humans introduced those egg-eating critters to Mauritius.
During the 19th century, the passenger pigeon was the most common bird in North America: and possibly in the world.
Between cutting down a great deal of this continent's forests, and industrial-level hunting, passenger pigeons became what we'd now call an endangered species.
Then, on September 1, 1914, the last known passenger pigeon died in the Cincinnati Zoo.The good news is that we've still got a bit of passenger pigeon DNA. Piecing those samples together and reviving the species is a bit beyond what we can do today: but not by much.
The real challenge may be in simultaneously raising enough passenger pigeons to re-start the species. Passenger pigeons were very social birds.
The 19th century saw hydraulic mining and London's death fog, but it wasn't all bad news.
A remarkable number of folks in America finally decided that owning other people was a bad idea.
New technologies like antiseptics and the McCormick reaper helped reduce the number of folks who died in epidemics and famines.
On the other hand, some folks got the notion that science and technology will solve all our problems, which I think is as daft as assuming the opposite. (October 26, 2014; December 31, 2012; April 22, 2012)
Quaternary Glaciation, Humanity's Backstory, and James Ussher
A series of extinctions started about 13,000 years back, we began developing agriculture about 12,000 years ago, and the 'it's our fault' extinctions started about 10,000 years ago.There's probably some truth to the assertion that we're involved in recent extinctions. But I think there's more to the story.
I don't doubt that we've had an effect: particularly in places like Mesopotamia, the Nile and Indus Valleys, and Zhongyuan. Replacing natural habitats with cropland couldn't help but make it hard for some critters to keep going.
But assuming that we're the only reason for species going extinct? That seems unlikely. Post hoc doesn't necessarily mean propter hoc.
Interestingly, our genus showed up around the time that the Quaternary glaciation started: and we've been dealing with a changing world ever since. (July 11, 2014)
We're still learning about humanity's backstory: but it's become obvious that we have been around for a very long time. We haven't always looked like we do now: but we've been acting human for well upwards of a million years.
I've talked about James Ussher, human origins, and getting a grip before. Fairly often. (October 31, 2014; July 15, 2014)
This post has gotten off-topic.
Bottom line about extinctions and being human: over the last 10,000 years or so, we've had an increasingly obvious effect on Earth's species.
The good news is that we are becoming increasingly aware of our power: and of the responsibility that goes with it.
"Little Less than a God" — Power and Responsibility
I'm a Catholic, so I must believe that God created and is creating a good and ordered universe. We're made in the image of God, rational creatures — and stewards of the physical world. (Genesis 1:27-28, Psalms 19:2; Wisdom 7:17; Catechism of the Catholic Church, 1, 341, 373, 1730, 2375)
That's stewards, not owners. We're in charge of this world, and responsible for its maintenance: but it does not belong to us. Part of our job is managing this world's resources for future generations. (Catechism, 373, 2415, 2456)
The vast scale of this universe, our power, and our responsibility — these aren't new ideas:"When I see your heavens, the work of your fingers, the moon and stars that you set in place -"What's changing is our growing realization of just how big and old the universe is, and how careful we must be.
"4 What are humans that you are mindful of them, mere mortals that you care for them?"
"5 Yet you have made them little less than a god, crowned them with glory and honor. "
(Psalms 8:4-6)
"How precious to me are your designs, O God; how vast the sum of them!
"Were I to count, they would outnumber the sands; to finish, I would need eternity."
(Psalms 139:17-18)
"The works of God are all of them good; in its own time every need is supplied."
"He has but to command and his will is done; nothing can limit his achievement."
"The works of all mankind are present to him; not a thing escapes his eye."
"His gaze spans all the ages; to him there is nothing unexpected."
(Sirach 39:16, 18-20)
That's careful, not fearful.
Like I've said before, science and technology, learning about the universe and using that knowledge, is part of being human. It's part of our job. (Catechism, 307, 2292-2295, 2415-2418)
God makes a universe, including us, that is "very good." Honest study of this creation cannot interfere with faith: because the things of faith and the things of this world are both created by God. (Genesis 1:31; Catechism, 35, 50, 159)
The problem isn't religion, science, or technology. What gets us in trouble is forgetting or ignoring our responsibilities. That, and original sin: which is another topic. (July 11, 2012)
Getting back to falling rocks, and what killed the dinosaurs —
Incoming!
(From NASA/Planetary Science, via Wikipedia, used w/o permission.)
("Frequency of small asteroids roughly 1 to 20 meters in diameter impacting Earth's atmosphere."
(Wikipedia))
That map shows two decades of known airbursts, releasing one to 1,000,000 GJ — geekspeak for gigajouls.
A joule is how much energy it takes to lift a small apple one meter. When we're resting, we release about 60 joules of energy — heat, mostly — every second. A gigajoule is 1,000,000 joules. Burning a barrel of oil releases about six gigajoules.
An airburst happened over a city in 2013.A rock about 17 meters, 56 feet, across exploded over Chelyabinsk, Russia, on February 15, 2013. More than a thousand folks were hurt, mostly by flying glass, a few buildings were broken, but nobody was killed.
Small meteors, from specks of dust up, are so common that I've seen them: and I'm not often out at night.
Folks have known about meteors — probably as long as we've been looking at the sky, which at last count is upwards of 2,500,000 years. Folks in Western civilization figured they were an atmospheric phenomenon, like lightning.
We were right, sort of. We don't see these bits of debris, left over from the Solar System's formation, until they hit Earth's atmosphere.
U.S. physicist and astronomer Denison Olmsted studied the 1833 Leonid meteor shower, and decided that meteors came from space. German physician and astronomer Heinrich Wilhelm Matthias Olbers predicted that there'd be another similar meteor shower in 1867.
Hubert Anson Newton, an American astronomer and mathematician, fine-tuned that prediction, and said that we'd see the Leonids in 1866. Italian astronomer and science historian Giovanni Schiaparelli connected the Leonids with Comet Tempel-Tuttle.
In 2010, Robert Marcus, H. Jay Melosh, and Gareth Collins developed the Earth Impact Effects Program, an online program "...for estimating the regional environmental consequences of an impact on Earth...."
That's enough name-dropping for one post. Maybe too much.
Here's a reasonable estimate of how often boulders are likely to fall out of the sky.
| Impactor diameter |
Kinetic energy at atmospheric entry |
Airburst energy |
Airburst altitude |
Average frequency |
|---|---|---|---|---|
| 4 m (13 ft) | 3 kt | 0.75 kt | 42.5 km (139,000 ft) | 1.3 years |
| 7 m (23 ft) | 16 kt | 5 kt | 36.3 km (119,000 ft) | 4.6 years |
| 10 m (33 ft) | 47 kt | 19 kt | 31.9 km (105,000 ft) | 10.4 years |
| 15 m (49 ft) | 159 kt | 82 kt | 26.4 km (87,000 ft) | 27 years |
| 20 m (66 ft) | 376 kt | 230 kt | 22.4 km (73,000 ft) | 60 years |
| 30 m (98 ft) | 1.3 Mt | 930 kt | 16.5 km (54,000 ft) | 185 years |
| 50 m (160 ft) | 5.9 Mt | 5.2 Mt | 8.7 km (29,000 ft) | 764 years |
| 70 m (230 ft) | 16 Mt | 15.2 Mt | 3.6 km (12,000 ft) | 1900 years |
| 85 m (279 ft) | 29 Mt | 28 Mt | 0.58 km (1,900 ft) | 3300 years |
Looks like we can expect something like the February, 2013, Russian airburst every three decades: on average.
Big impacts — like those ones that left the Chicxulub, Kara, and Popigai, craters — come at intervals of tens of millions of years. Then there are really big ones, like the Vredefort impact.
Bear in mind, "average frequency" is just that: an average. These things don't come on a regular schedule. This morning's news might include a Chelyabinsk-size airburst: or we may not see another for a hundred years.
An important point, I think, is that really big rocks don't come nearly as often as little ones.
That's good news, because hunks of rock the size of a city block and larger do a lot of damage.
The hypothetical rocks in these tables hit Earth at a 45 degree angle, going 17 kilometers a second. That's a typical speed and angle for an incoming asteroid. (Impact event, Frequency and risk (Wikipedia))
Impactor diameter |
Kinetic energy at atmospheric entry |
Impact energy |
Crater diameter |
Average frequency |
|---|---|---|---|---|
| 100 m (330 ft) | 47 Mt | 38 Mt | 1.2 km (0.75 mi) | 5200 years |
| 130 m (430 ft) | 103 Mt | 64.8 Mt | 2 km (1.2 mi) | 11000 years |
| 150 m (490 ft) | 159 Mt | 71.5 Mt | 2.4 km (1.5 mi) | 16000 years |
| 200 m (660 ft) | 376 Mt | 261 Mt | 3 km (1.9 mi) | 36000 years |
| 250 m (820 ft) | 734 Mt | 598 Mt | 3.8 km (2.4 mi) | 59000 years |
| 300 m (980 ft) | 1270 Mt | 1110 Mt | 4.6 km (2.9 mi) | 73000 years |
| 400 m (1,300 ft) | 3010 Mt | 2800 Mt | 6 km (3.7 mi) | 100000 years |
| 700 m (2,300 ft) | 16100 Mt | 15700 Mt | 10 km (6.2 mi) | 190000 years |
| 1,000 m (3,300 ft) | 47000 Mt | 46300 Mt | 13.6 km (8.5 mi) | 440000 years |
If rocks 100 meters across hit every 5,200 years, on average, how come we don't have records of an impact like that?
Again, these are averages.
Maybe there hasn't been one since some of us started keeping records: about 5,200 years ago.
Back then, the First Dynasty of Egypt was laying the groundwork of Pharaonic Egypt, and the Liangzhu culture was creating jade masks.
If something blasted a kilometer-wide hole in those days, the odds are pretty good that it happened far from these comparatively high-tech centers. Besides, about three quarters of this planet is covered in water.
That was then, this is now, and there's a pretty good chance that another airburst will break windows: at least.
1. Learning from Chelyabinsk?
(From Alex Alishevskikh, cyberborean.org; via Flikr and Space.com, used w/o permission.)
("Trail of the object that exploded over Chelyabinsk, Russia, in 2013."
(Space.com))
"What Can We Do If an Asteroid Threatens Earth? Europe Starts Planning"I don't doubt that this is the first time European government officials ran this particular simulation.
Elizabeth Howell, Space.com (January 13, 2015)
"What should humanity do the next time a space rock threatens Earth? European officials recently spent two days figuring out possible ways to respond to such a scenario, with the aim of drawing up effective procedures before the danger actually materializes.
"The first-of-its-kind simulation considered what to do if an asteroid similar to, or larger than, the one that exploded over Russia in February 2013 — which was about 62 feet (19 meters) wide — came close to Earth. Officials focused on activities ranging from 30 days to 1 hour before a potential impact.
" 'There are a large number of variables to consider in predicting the effects and damage from any asteroid impact, making simulations such as these very complex,' Detlef Koschny, head of near-Earth-object activities at the European Space Agency's Space Situational Awareness office, said in a statement...."
The implication that they're the first to take a serious look at what happens and what should be done when rocks fall out the sky is — a tad exaggerated. (February 21, 2014)
Still, credit where credit is due.
European officials took a look at what to expect if — when — a rock between 12 and 38 meters, 39 and 125 feet, across comes in at 45,000 kilometers an hour: 28,000 mph.
They took a look at what could be done 30, 26, 5 and 3 days before impact: and an hour afterward. Here's a sample of what they decided, from an ESA press release:
"...'For example, within about three days before a predicted impact, we'd likely have relatively good estimates of the mass, size, composition and impact location,' says Gerhard Drolshagen of ESA's NEO team.
" 'All of these directly affect the type of impact effects, amount of energy to be generated and hence potential reactions that civil authorities could take.' "
(European Space Agency (December 18, 2014))
With 30 days lead time, and a pretty good idea of where something like the Chelyabinsk object would hit, I'd like to think that "civil authorities" would have time to fill out the proper forms — and let folks know when to head for an inside room with no windows.That would be a huge improvement over being surprised by a second sun shooting across the sky.
What about the presumed danger of mass hysteria, as commoners panic in the streets?
Let's look at what happened in 1953.
The Worcester Lesson, and Business As Usual
June 7, 1953: A high-pressure air mass tangled with its low-pressure counterpart over Nebraska. That's thunderstorm and tornado weather.June 7 - June 8, Tornadoes moved across Nebraska, Ohio, and Michigan. More than a hundred people died.
The storms kept moving east, into New York state and the New England area.
That part of the continent generally doesn't get tornadoes: but they do happen.
Forecasters at the National Weather Service office, Boston, looked at the numbers, and thought tornadoes were possible.
They didn't want to panic the hoi polloi, so they didn't include tornadoes in the official forecast.
Deucedly thoughtful of them.
4:25 PM, June 8: boaters on the Quabbin Reservoir in Petersham, Massachusetts, saw tornadoes.
5:08 PM: a tornado arrived at Worcester, Massachusetts. It was a big one, a mile across after it entered Worcester.
A building with three-foot-thick brick walls at Assumption College lost its top three floors. Houses in the Uncatena-Great Brook Valley neighborhoods disappeared. The twister was still a mile across when it hit Shrewsbury.
After killing 81 people in Worcester, Shrewsbury, Southborough, and Westborough, the tornado finally dissipated.
Starting June 17, 1953, the Storm Prediction Center got reorganized. Later, we set up a nationwide radar/storm spotter system.
It wasn't until the big Joplin tornado that more than a hundred folks died in a single storm. (May 25, 2011)
Here in the upper Midwest, tornado alerts and warnings are a summer routine. I'm pretty sure that most folks are as capable of taking common-sense precautions as we are.
Right now, the problem seems to be getting that 30-day warning before impact.
The trick is finding and keeping track of a great many house- to sports-stadium-size objects scattered around the inner Solar System.
The U. S. Congress referred "H.R. 5587 (111th): To establish a United States Commission on Planetary Defense, and for other purposes" to committee in 2010, effectively killing the bill. Eventually, I think we'll decide that keeping asteroids from hitting Earth is a good idea.
Someone's already pointed out that technology for pushing asteroids away from Earth could be misused. I think the chap's right. Like it says in the Bible:
"2 But man himself begets mischief, as sparks fly upward."There hasn't been a technology, from fire and string to anesthetics and computers, that someone hasn't misused. But I don't think the answer is abandoning fire and hoping for the best. And that's yet another topic. (April 27, 2014)
(Job 5:7)
More:
- "Preparing for an asteroid strike"
space situational awareness, ESA press release (December 18, 2014) - Asteroid impact avoidance (Wikipedia)
2. SpaceX Cargo Run: Delivery Okay, Landing Not So Much
(From SpaceX, via BBC News, used w/o permission.)
("The Falcon's onboard cameras capture the moment the first stage separates to begin its return"
(BBC News))
"SpaceX launches cargo ship but rocket recovery test ends in crash"A next step in dealing with incoming asteroids and comets will be commercial transportation services like SpaceX's Falcon. (May 2, 2014)
Jonathan Amos, BBC News (January 10, 2015)
"The American SpaceX firm says its experiment to bring part of its Falcon rocket down to a soft landing on a floating sea platform did not work.
"The vehicle was launched on a mission to send a cargo capsule to the International Space Station.
"But once the first-stage of the rocket completed its part of this task, it tried to make a controlled return.
"The company CEO Elon Musk tweeted that the booster had hit the platform hard.
" 'Close, but no cigar,' he added. 'Bodes well for the future tho'. Ship itself is fine. Some of the support equipment on the deck will need to be replaced.' And he continued: 'Didn't get good landing/impact video. Pitch dark and foggy. Will piece it together from telemetry and... actual pieces.'..."
Knowing that a hunk of rock is coming is good. Flying out to meet it, and maybe deflecting the thing: better.
This particular flight's Dragon cargo module is fine, by the way. It delivered food, spare parts and scientific experiments to the ISS a few days ago. (Space.com (January 12, 2015))
I like the SpaceX approach: letting a routine cargo run double as a test flight for a reusable first stage. It's also good to see that SpaceX is still working on their resuable booster. (December 28, 2012)
Reaction Engines Limited's Skylon spaceplane will be ready for test flights in 2019, and cargo runs in 2022: if development stays on schedule, and that's almost another topic.
Hypersonic Grid Fins and Hydraulic Fluid
(From MIT Technology Review, used w/o permission.)
("The Falcon 9 rocket launches from Cape Canaveral, Florida, carrying a payload destined for the International Space Station."
(MIT Technology Review))
"SpaceX Claims Partial Success with Rocket Crash Landing"
Dave Majumdar, MIT Technology Review (January 12, 2015)
"Success would redefine the economics of space travel, but SpaceX's reusable rocket shows that it's still hard to perform a safe landing.
"As if launching a rocket into space weren't enough, on Saturday SpaceX tried to bring one safely back to earth by setting it down on a floating landing pad....
"...After releasing the second stage, the boosters of the Falcon 9 first stage oriented the 14-story-tall rocket vertically as it sank back down to earth and controlled its descent. Sticking the landing is tricky because the rocket's speed must be controlled carefully, and the correct orientation requires very fine control of the vehicle's thrusters, as well as several hydraulic fins....
"...Musk blamed the hard landing on a failure of the four 'grid' fins used to steer the first stage on its descent. 'Grid fins worked extremely well from hypersonic velocity to subsonic, but ran out of hydraulic fluid right before landing,' he wrote in another tweet.
"This is why most previous attempts at reusable launchers have taken the form of space planes like the Space Shuttle or the Air Force’s semi-secret X-37. These vehicles are very complex and expensive. Some rockets have been designed to be recovered via parachute. While this is cheap and reliable, it also takes a long time to recover and recondition the rocket for another launch...."
That SpaceX photo shows a similar set of grid fins on their Falcon 9.Maybe Elon Musk is 'making the best of a bad situation,' presenting a failed landing as a partial success.
But let's remember that the Dragon cargo module arrived at the ISS on schedule: and SpaceX apparently has a pretty good idea about what went wrong with the Falcon 9 landing.
Running out of hydraulic fluid before landing is embarrassing, at best. But it strikes me as something that can be corrected for future flights.
SpaceX test-flew a similar booster in 2014: a short hop, one kilometer up, then back down.
"F9R Flight Test | 1,000m"
SpaceX, YouTube (May 2, 2014)
We're not at the point where space travel is as routine as air travel is today: but we're getting there.
Developing vehicles we can use more than once is a huge step in that direction.
More about using our brains:
- "Sagittarius B2, Water, and Asteroid Mining"
(October 3, 2014)
Particularly - "Lowering Costs on the Earth-to-Orbit Run, Preparing for Incoming Asteroids"
(May 2, 2014)
Particularly - "Tunguska and Chelyabinsk Airbursts: Risk, Rocks, and Readiness"
(November 8, 2013)
Particularly - "Asteroids, Comets, and Doing Our Job"
(September 29, 2013)
Particularly - "Ethics and Asteroids"
(February 20, 2013)
Particularly
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