from the making-humans-not-be-like-the-dinosaurs dept.
EurekAlert reports: "NASA to map the surface of an asteroid"
NASA's OSIRIS-REx spacecraft will launch September 2016 and travel to a near-Earth asteroid known as Bennu to harvest a sample of surface material and return it to Earth for study. The science team will be looking for something special. Ideally, the sample will come from a region in which the building blocks of life may be found.
The Daily Mail points out:
Bennu crosses Earth's orbit once every six years and is set to pass between the moon and our planet in 2135.
Scientists are worried the 500-metre wide asteroid's orbit could be tweaked by Earth's gravity as it passes by, causing it to smash into our planet later in the century.[...] 'We estimate the chance of impact at about one in 2,700 between 2175 and 2196,' [Prof. Lauretta] said.
It seems this (paywalled) Sunday Times article might be the original source for the quotes from Prof. Lauretta. Here are some excerpts from the article:
"Bennu is a carbonaceous asteroid, an ancient relic from the early solar system that is filled with organic molecules," said Lauretta.
"Asteroids like Bennu may have seeded the early Earth with this material, contributing to the primordial soup from which life emerged."
[...] For scientists, the chance of obtaining chunks of a carbonaceous asteroid is exciting. For the rest of us, however, Osiris-Rex's most important task may be the measurements it makes of a bizarre and newly discovered force that can send asteroids careering around the solar system and potentially towards Earth.
"The Yarkovsky effect is the force that acts on an asteroid when it absorbs sunlight and then radiates it back into space as heat. It acts like a small thruster, constantly changing its course," said Lauretta. "Bennu's position has shifted 160km [100 miles] since 1999."
It is these forces that make Bennu's trajectory so hard to predict after 2135's near-miss. It is expected to pass Earth at a distance of about 180,000 miles, well inside the moon's orbit and close enough to alter the asteroid's path so it may hit our planet on a future orbit.
Related Stories
CNET reports that two asteroids, 2017 FU102 and 2017 FT102, passed the Earth on 2 April and 3 April.
The near-Earth asteroid 2017 FU102 was discovered by the Mt. Lemmon Survey in Arizona (USA) on 29 March 2017. Today (April 2, 2017), it will have a very close, but safe encounter with the Earth (about 0.6 times the mean distance of the moon).
[...] this ~10 meters large rock will reach its minimum distance from us of 143,000 miles (230,000 km).
The other object, 2017 FT102, is smaller and its approach to the Earth was at a greater distance. It was also discovered on 29 March.
[By comparison, the Chelyabinsk meteor was estimated to be 20 meters in diameter. --Ed.]
NASA reports, via NASA, that OSIRIS-REx is leaving Bennu.
NASA's OSIRIS-REx completed its last flyover of Bennu around 6 a.m. EDT (4 a.m. MDT) April 7 and is now slowly drifting away from the asteroid; however, the mission team will have to wait a few more days to find out how the spacecraft changed the surface of Bennu when it grabbed a sample of the asteroid.
The OSIRIS-REx team added this flyby to document surface changes resulting from the Touch and Go (TAG) sample collection maneuver Oct. 20, 2020. "By surveying the distribution of the excavated material around the TAG site, we will learn more about the nature of the surface and subsurface materials along with the mechanical properties of the asteroid," said Dr. Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona.
During the flyby, OSIRIS-REx imaged Bennu for 5.9 hours, covering more than a full rotation of the asteroid. It flew within 2.1 miles' (3.5 kilometers) distance to the surface of Bennu – the closest it's been since the TAG sample collection event.
Just to mention, the survey and selection of a sampling site was one of the recent "citizen science" projects.
(Score: 4, Informative) by butthurt on Monday August 01 2016, @06:17AM
http://www.independent.co.uk/news/science/nasa-probe-asteroid-armageddon-bennu-space-a7164901.html [independent.co.uk]
https://www.ibtimes.co.uk/nasa-probe-study-asteroid-its-next-near-miss-earth-2018-1573472 [ibtimes.co.uk]
(Score: 0) by Anonymous Coward on Monday August 01 2016, @06:44AM
smash into our planet later in the century.
And nothing of value will be lost.
(Score: 0) by Anonymous Coward on Monday August 01 2016, @09:12AM
"An ancient relic from the early solar system that is filled with organic molecules," would be lost. That would be sad.
(Score: 2) by GreatAuntAnesthesia on Monday August 01 2016, @09:51AM
Actually, two of them would be lost.
(Score: 2) by bob_super on Monday August 01 2016, @09:40PM
But only one qualifies as Mostly Harmless.
(Score: 2) by Justin Case on Monday August 01 2016, @11:46AM
I'm sure the Presidency of Chelsea Clinton will be over and done by 2135, so no need for any current politician to care about this.
(Score: 2) by Scruffy Beard 2 on Monday August 01 2016, @01:52PM
That is well within 7 generations.
According to North American native culture, that is about how far ahead you should plan. Studying this rock on the way by is just prudent from that point of view.
(Score: 0) by Anonymous Coward on Monday August 01 2016, @01:03PM
Anyone know how they estimated this? I fear they used confidence intervals and are incorrectly interpreting the output.
(Score: 1, Informative) by Anonymous Coward on Monday August 01 2016, @01:08PM
The best I found was this, which says my feeble mind can't comprehend their calculations so dont worry bout it:
http://neo.jpl.nasa.gov/risk/a101955.html [nasa.gov]
(Score: 2, Interesting) by Anonymous Coward on Monday August 01 2016, @01:46PM
Ok, I followed the links from the NASA page to this paper and what I found is concerning. It looks like they are doing monte carlo simulations but only sampling object positions from what they call a 3-sigma "confidence region" (if I understood correctly, this region confusingly does not have much relationship to the usual frequentist concept of "confidence").
Anyway, that means the tails of the distribution are being truncated, which will lead to chronic underestimation of the risk. They say this is done because the simulations are too inefficient, but that argument is based on 2002 tech. Something that took a week in 2002 could probably be done in a few seconds now. I wish they would just share the exact code being used today.
http://www.lpi.usra.edu/books/AsteroidsIII/pdf/3040.pdf [usra.edu]
(Score: 3, Interesting) by VLM on Monday August 01 2016, @01:04PM
"The Yarkovsky effect is the force that acts on an asteroid when it absorbs sunlight and then radiates it back into space as heat. It acts like a small thruster, constantly changing its course," said Lauretta. "Bennu's position has shifted 160km [100 miles] since 1999."
Maybe if its on a collision course global warming could save us.
I'm too lazy to run the numbers but "obviously" there is a small net force due to the sunlit side of the planet being warmer and radiating away more IR than the cold dark side of the earth. Surely that force varies with global warming due to changes in dew point and fuzzy math and butterflies flapping wings causing chaos and stuff. I'd be shocked if the net force were exactly zero WRT delta in average surface temp.
Any force will have an effect on orbital position that cascades over time. Space is really freaking big and the earth is really freaking small like 4000 miles diameter. So if an asteroid were bullseye to hit the earth in 50Myrs killing everything again dinosaur style, it turns out that moving the earth (or anything) 5000 miles in 50Myrs is 5000 / 50e6 / 365 / 24 or about ten billionths of a mile per hour. To one sig fig, not accounting for leap years doesn't matter a hell of a lot. Also the relevant atmosphere is a lot thinner than 1000 miles, in fact 100 miles up is more than adequate for a miss. But whatever.
I have no idea how ten billionths of a MPH fits in with the surface of the earth as an infrared thruster. Note that there's many orders of magnitude to play with if you want.
I'm forever coming up with interesting hard sci fi novel ideas and this could make an interesting plot. Space aliens use propaganda in the 1900s to convince us to burn all our planets oil in 100 years to make sure a planet killer asteroid misses us in 50M years. Or the reverse, I suppose, burning the oil today is moving us into the crosshairs in 50 Myrs. Either way it would make a semi-entertaining hard sci fi novel plot. In my infinite spare time. Or James Bond villain time they just want to make sure the "right" country is hit by a small meteor, big enough to be entertaining.
(Score: 2) by FatPhil on Monday August 01 2016, @03:55PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by VLM on Monday August 01 2016, @04:48PM
Agreed it would be more efficient from an engineering standpoint to launch a mission to the asteroid with a truly huge can of paint. Which as a tangent would be an interesting hard sci fi plot.
Hmm so the helpful space aliens need to alter the orbit without a mission because 1) we might fail to launch a mission but its hard to screw up "set stuff on fire" and 2) They are not here or not here with high tech, like the usual stranded astronaut story or some kind of radio communication. or 3) alternatively they just like messing with us. Space aliens get bored too.
(Score: 2) by Thexalon on Monday August 01 2016, @01:21PM
We have to wait until the last possible moment, put a completely untrained oil drilling roughnecks into space shuttles, fly them to the asteroid, somehow land on it, use the oil-drilling equipment to dig down into the asteroid, and then have the leader of the roughnecks manually detonate a nuke at the cost of his own life.
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 0) by Anonymous Coward on Monday August 01 2016, @01:57PM
Instructions unclear.
Got dick stuck in toaster.
(Score: 2, Interesting) by dierdorf on Monday August 01 2016, @04:09PM
The Yarkovsky effect on asteroids and comets was first published in 1900 and is well-known to astronomers. I don't regard that as "recent" in terms of scientific discoveries. I remember reading a science fiction story in the 50's where the orbital shift of a comet due to the Yarkovsky effect was part of the plot. As far as "bizarre", may I assume these scientists know about photons having momentum?
(Score: 1, Interesting) by Anonymous Coward on Monday August 01 2016, @05:39PM
This is a well known phenomenon:
http://andrewgelman.com/2014/08/01/scientific-surprise-two-step/ [andrewgelman.com]
(Score: 2) by Open4D on Tuesday August 02 2016, @01:00AM
NASA's Mission to "Bennu", the Asteroid that Might Kill Your Grandchildren
If, for example, you are currently young, and are still able to have a son in 25 years time. And if that son is 45 years old when he has a daughter. Then she, your granddaughter, would be about 89 years old in 2175.