[HN Gopher] Discovered June 16th, large asteroid to pass between...
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Discovered June 16th, large asteroid to pass between Earth and moon
on Saturday
Author : whycome
Score : 68 points
Date : 2024-06-28 16:45 UTC (6 hours ago)
(HTM) web link (www.cbc.ca)
(TXT) w3m dump (www.cbc.ca)
| metadat wrote:
| Was funding for the Asteroid Watch program drastically reduced,
| or why did the detection come in so late?
|
| https://www.jpl.nasa.gov/asteroid-watch
| burnte wrote:
| The sky is really big. No detection will ever be 100%.
| dylan604 wrote:
| Your application for a tourist visa to the Earth Planetary
| Visitor's Bureau has been denied due to a clerical error.
| Please alter your course to enter a holding orbit until your
| application has been resubmitted. We thank you in your
| interest in visiting Earth.
| jfoutz wrote:
| For various reasons Armageddon is one of my favorite movies.
| Action/comedy, not exactly _good_ but I find it enjoyable.
|
| I bring it up because of the Fictional mission commander
| talking to the president,
|
| > Begging your pardon sir, but its a big ass sky.
| foobarian wrote:
| The best thing about Armageddon for me are open flames in
| vacuum.
| iam-TJ wrote:
| I'm confused about the late warning quote because the data page
| for MK2024 shows the first observation for the orbit fit was
| 2024-05-07.
|
| https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2024%...
| dylan604 wrote:
| So even if they announced on the day of the first
| observation, that's not really much notice to do anything
| about it other than start prepping for accepting of loss of
| life. I would seriously hope it took some amount of time for
| other people to verify/validate trajectory than the first
| person that observes it.
|
| At this point, we're still at the point of needing years if
| not decades notice for us to even have a chance of actually
| protecting from an impact in a meaningful way.
| prewett wrote:
| I figure we could get a Falcon Heavy filled with rocks or
| something launched in a hurry. But, I did the math, and
| like you say, all we could do is watch.
|
| Assuming the standard asteroid density of 2000 kg/m^3 [1],
| a 260 m diameter asteroid has a volume of 4/3 * pi * 130^3
| = 1.84e10 m^3. Falcon Heavy can lift 16818 kg to a transfer
| orbit to Mars [2], which I assume is basically what it can
| do to reach an asteroid coming at us. A normal speed of
| space probes (without gravity assists) seems to be about
| 25,000 mph = 11600 m/s. Thus, it has a momentum of about
| 1.95e8 kg*m/s.
|
| Assuming we hit the asteroid perpendicular to its motion,
| transferring all our momentum into transverse velocity,
| that is 1.95e8 / 1.84e10, or approximately 0.01 m/s. To
| ensure a miss, it would need to travel the whole diameter
| of the earth, 6.378e6 m, which would take 6.378e8 seconds,
| or about 20.2 years, which is the amount of time before
| impact we would need to hit the asteroid.
|
| We would probably have more success hitting it head on.
| Since the earth is moving at about 3e4 m/s, we only need to
| delay the asteroid by 213 seconds. The minimum speed of an
| asteroid impacting Earth is 1.1e4 m/s, so we would need to
| move it backwards 2.343e6 m. This allows us to hit it
| slightly later, only 7.3 years ahead of time (in the best-
| case scenario). Assuming it could vary by a factor of two,
| we would need up to about a 14 year lead time.
|
| [1] https://en.wikipedia.org/wiki/Standard_asteroid_physica
| l_cha...
|
| [2] https://en.wikipedia.org/wiki/Falcon_Heavy
|
| [3] https://en.wikipedia.org/wiki/Impact_event
| alkyon wrote:
| I haven't done any calculations but wouldn't they use
| nuclear warheads to deflect it?
| SoftTalker wrote:
| > start prepping for accepting of loss of life
|
| If they knew it was going to hit, but not be an extinction
| event, maybe that makes some sense but realistically what
| kind of "prepping" can reasonably be done? Stock up on
| toilet paper?
|
| If they knew it was going to hit and incinerate the surface
| of the earth, would they even say anything? Why create
| worldwide panic for no purpose?
| ant6n wrote:
| If the asteroid was gonna be like a large nuclear
| explosion, perhaps one could evacuation the directly
| affected areas.
| whycome wrote:
| Because they had to time the asteroid to show up for World
| Asteroid Day obviously.
|
| https://asteroidday.org/about/
|
| (June 30th, since 2014)
| phkahler wrote:
| "Maybe the big take-home point on this one is it's a pretty big
| object and it was only found 10 or 12 days before closest
| approach,"
|
| I've said this before. The way they find these things is looking
| for movement against the distant background / starfield. That
| works pretty well for finding things, but there is one problem.
| Any object on a collision course with earth will NOT be moving
| across the background in the days leading up to the collision. It
| will appear stationary against the stars, so will not be detected
| by these systems. To some extent it also doesn't matter that we
| are orbiting the sun because while near, earth and asteroid will
| be in the same accelerating reference frame.
|
| Another way to model it is to think of firing a projectile _from_
| earth into deep space and see how that tracks against the
| background. That 'd be the reverse scenario and there will be no
| relative motion until it's far enough to not get the same
| influence from the sun.
| rbanffy wrote:
| One more reason for deep space telescopes. A PHA about to
| impact will not have much movement in relation to the
| background stars when seen from Earth, but will be moving when
| seen from a different vantage point.
| kemiller wrote:
| Sounds like we need a monitoring station on Mars.
| s1artibartfast wrote:
| >It will appear stationary against the stars, so will not be
| detected by these systems. To some extent it also doesn't
| matter that we are orbiting the sun because while near, earth
| and asteroid will be in the same accelerating reference frame.
|
| I dont think that is true aside from the case where the
| asteroid vector is the exact opposite of the earth.
|
| Even if the earth and the asteroid are in the same accelerating
| reference plane, the background is not.
|
| If you have two race cars going in around a track and at one
| from the other, it still appears to be moving relative to the
| stands.
| mike_d wrote:
| > If you have two race cars going in around a track and at
| one from the other, it still appears to be moving relative to
| the stands.
|
| Right. Now put the stands on another planet and you start to
| understand the problem.
|
| We need to be able to see an asteroid at a _minimum_ of of
| 3-4x the distance between the earth and the sun to have
| enough time to do anything about it based on the average
| speed of 40k mph.
|
| Now keep in mind that at that distance you are looking for
| something as "tiny" as 60 miles across, the accepted size
| that would unquestionably end life on earth. Something ~1km
| across would cause mass famine. In 1908 an asteroid less than
| 200 feet across flattened 80 million trees over an 830 square
| mile area.
| s1artibartfast wrote:
| Even if the stands are far away, even light years away, you
| pan through 360deg every year. The fact that the background
| is far away means that it moves even quicker relative to a
| nearby object in a rotational frame.
|
| If you spin around in a circle, hold your hand out and look
| at it, it will be moving very quickly against a distant
| background, like the horizon.
|
| My point is that the distance to the background helps
| detection, not hurts it. If the background was nearby and
| co-rotating around the Sun, detection would be a near
| impossible.
| EA-3167 wrote:
| What you're describing is known as Constant Bearing, Decreasing
| Range (CBDR),
| https://en.wikipedia.org/wiki/Constant_bearing,_decreasing_r...
| and generally doesn't apply to to the case of a _nearby_
| asteroid on a collision course with Earth. For the parallax
| created by our orbit to be negligible, the object would have to
| be very distant.
| pocketstar wrote:
| This is an incredibly naive approach. All asteroids emit light
| in the infrared, to detect and track asteroids just takes an
| infrared telescope making apparent motion against any
| background completely irrelevant. NASA is working on this:
| https://en.m.wikipedia.org/wiki/NEO_Surveyor
| squarefoot wrote:
| > Any object on a collision course with earth will NOT be
| moving across the background in the days leading up to the
| collision.
|
| Earth itself moves, so anything appearing static would be easy
| to spot since it's the background that also moves relative to
| an observer.
| jfengel wrote:
| How large? "anywhere from 120 metres to 260 metres in diameter".
|
| Is that bad? According to NASA, "If a rocky meteoroid larger than
| 25 meters but smaller than one kilometer ( a little more than 1/2
| mile) were to hit Earth, it would likely cause local damage to
| the impact area. We believe anything larger than one to two
| kilometers (one kilometer is a little more than one-half mile)
| could have worldwide effects."
|
| So... it would really suck if it hit a populated area, though
| that's unlikely.
| dylan604 wrote:
| I'm surprised there's no TNT equivalent comparing it to the
| biggest weapons humans have created. That always seems like a
| data point used when showing destructive forces.
| biot wrote:
| From the article:
|
| _> "This is a big object. An object of this size is going to
| have the equivalent impact energy in the hundreds of megaton
| approaching a gigaton," Brown said. "That'd be a regional
| impact. It's the sort of thing that if it hit the east coast
| of the U.S., you would have catastrophic effects over most of
| the eastern seaboard. But it's not big enough to affect the
| whole world."_
| throwthrowuknow wrote:
| Not very comfortable with how much that sounds like
| downplaying the effects. It would be the largest disaster
| in all of human history. For reference the estimated
| strategic nuclear arsenal of the United States is about 820
| megatons and the largest US test detonation was 15 megatons
| so an impact of this size would be on par with or possibly
| worse than an all out nuclear war between the US and
| Russia. God knows what kind of effects that kind of blast
| would have, it would probably kill half the US population
| on impact and light the entire east coast on fire. No idea
| what would happen to the rest of the world after that but
| the supply chain "disruption" alone would mean millions
| starving and without fuel or medicine.
| avar wrote:
| Nuclear weapons are targeted, an asteroid releasing 1000x
| the amount of energy of all the world's nuclear weapons
| isn't going to be 1000x worse. Perhaps it'll vaporize on
| impact in the middle of the Pacific.
| johnnyanmac wrote:
| well the Chicxulub impactor (The one that ended the Cretaceous
| Period) was estimated to be 10-15km. on the other end, the
| largest recorded asteroid in Siberia was 50-60m in size and did
| local but very noticeable damage[1], apparently 4x as powerful
| as the nuclear bomb that hit Hiroshima.
|
| So 260m would be absolutely devastating, but wouldn't end
| civilization as we know it. it would absolutely destroy any
| state or smaller country it hit. if it hit/exploded above an
| ocean, we'd have record breaking tsunamis completely flood
| whatever coastal areas it hit.
|
| 1: https://www.euronews.com/culture/2023/06/30/culture-re-
| view-...
| hyperpape wrote:
| I can't vouch for this being perfectly accurate, but it's
| appeared here on HN before: https://neal.fun/asteroid-launcher/
| CaptainOfCoit wrote:
| The amount of "suckage" in case it would hit Earth is mentioned
| in the article:
|
| > Fortunately, it won't impact Earth. But it would be a bad day
| if it did. "This is a big object. An object of this size is
| going to have the equivalent impact energy in the hundreds of
| megaton approaching a gigaton," Brown said. "That'd be a
| regional impact. It's the sort of thing that if it hit the east
| coast of the U.S., you would have catastrophic effects over
| most of the eastern seaboard. But it's not big enough to affect
| the whole world."
| rich_sasha wrote:
| My physics might be wrong, but with Earth's radius at 6500km and
| Lunar orbit radius around 350,000km, probability of a collision
| course given asteroid being within a lunar orbit distance is only
| (6.5/350)^2 or 0.03%, or maybe even cleaner, 1 in 3000. So it's
| not _that_ close a miss.
| EA-3167 wrote:
| In terms of these things, its a hair's breadth, but in human
| terms it's incredibly distant. We don't have a _great_
| intuition about just how enormous and empty space is, how much
| of the universe (including our little patch) is just a seething
| void.
| rich_sasha wrote:
| It's not about intuition, it's about probability of impact.
| All these articles talking about asteroids flying within a
| lunar orbit distance make it sound like we got away lucky.
| But that's still far, far away, and the chances of impact are
| quite remote, in absolute terms.
| throwthrowuknow wrote:
| Cool but what's its orbital period and how does this close pass
| effect future crossings?
| philsnow wrote:
| I recall that Google has a library that will answer the question,
| "given two identifiers like cluster names or machine names, which
| failure domains do they share?". Those failure domains can be
| like "they're in the same rack", "they share a power bus",
| "they're in the same physical building", "they're in the same
| geographical region", that kind of thing.
|
| I wonder if it has since been updated to account for different
| disaster scenarios. It would be good to know, if you're storing 5
| redundant copies of something critical, that all 5 copies won't
| be under 10 feet of water if an asteroid strikes one of the poles
| and melts all that pole's ice.
|
| I can't imagine what data would be so critical that it's
| important to make sure it survives such an event, but that hasn't
| stopped googlers over-engineering internal things in the past.
| pigscantfly wrote:
| The LOCKSS [1] digital preservation threat model (I've been
| told, there's a whitepaper if curious) considers nuclear first
| strikes and large solar storms -- they maintain a global
| network of servers for archiving and preserving academic
| research.
|
| [1] https://www.lockss.org/why-lockss
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