# If an asteroid was to collide with Earth, how much warning would we have?

We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

I was talking to my 9-year-old son about the Florence asteroid that is passing close to the earth. He wanted to view youtube videos about that asteroids, and we saw the starting of this one https://www.youtube.com/watch?v=UzxMbkrNbcg and when I realized that the title video has 2036 as the year in which an asteroid crashes into the Earth. I explained that that was science fiction (like Back to the future) and only an animation

He asked me: "If an asteroid or similar object was to collide with the Earth,… how many years or months before the crash occurs would the scientific community know?"

I suppose that the advance time depends on technology, so assume the current level of technology.

Asteroids come in all shapes and sizes, and generally the bigger they are the easier they are to detect.

Small asteroids, from a the size of sand grains (properly called meteoroids) to a few meters across hit the Earth everyday without causing harm and are undetectable until they hit (we call the trace as they hit the atmosphere a meteor) They cause no damage. For such objects we get 0 hours warning.

Somewhat larger objects can cause some local damage For example the Chelyabinsk asteroid caused damage from broken glass in Russia. Objects this large may be detected a few hours to a few days. The Chelyabinsk asteroid wasn't, and hit with no warning. We have observed some small asteroids just prior to them hitting the atmosphere.

We have found large numbers of objects whose orbit can bring them close to Earth. Every object we have found has an orbit that misses Earth. With each new object that is located we can forecast its orbit for several centuries. However new objects are being found all the time. It is possible that a object will be discovered that has the potential to cause damage to a wider area. If the object happened to be on an orbit that had it collide with Earth then there could be less than a year's warning. That is very unlikely. It is slightly more likely that an object will be discovered to be on a collision course only after several orbits, in which case there would be years or decades warning.

Very large objects that could threaten the survival of humankind are rare. There are some such objects, (larger than Florence). We hope that we have now detected all very large near Earth asteroids, and discoverd them to be non-threatening (like Florence is not a current threat to Earth)

Finally a comet may be on a collision course with Earth. Comets that are spotted are usually detected a few months before they could threaten Earth. But comets are much rarer than asteroids.

In summary, between 0 hours and a century, with several decades being likely for an object that could do widespread damage.

The particular object referred to in the video is Apophis. It is roughly 400m asteroid that is not going to hit the Earth for as long as we can forecast. It will, however, pass close by in 2029, and again in 2036. In 2005 the uncertainty in orbit was such that we could not rule out a collision in 2036. Further observations in 2006 and after allowed and a more accurate orbit to be calculated, and showed that it would certainly miss.

## Earth-Crossing Asteroids

Pan-STARRS telescope under construction on Maui. Image by Pan-STARRS. Used with permission.

Can we do anything about an asteroid that is destined to hit the Earth? The answer is, yes, providing that it is small enough and that we have enough time to send a spacecraft to deflect it. As we will see, the longer the warning time we have, the larger the asteroid we will be able manage. Many of the aspects of asteroid impact mitigation were summarized in the Spaceguard Report. More recently, NASA has also completed a study and is being used by congress to decide what steps the US and other nations can and should take.

Astronomers have spent a lot of time trying to figure out how to save the Earth from an asteroid impact. First you have to find all the asteroids, calculate their orbits and see which ones come dangerously close to Earth. Once you know the orbit, you can figure out when it will hit. This tells you how much warning time you have. And finally, if you can figure out the asteroid’s mass, you can compute how hard you have to push it in order to change its orbit just enough to miss the Earth. Hollywood’s notion of sending a bomb to “blow it up” is unrealistic because present-day launch vehicles can’t carry a big enough bomb. Besides, instead of one large body, you might end up with many small fragments headed toward Earth.

## How Do You Stop a Hypothetical Asteroid From Hitting Earth? NASA's On It.

We'll have to deflect a space rock someday. It's just a question of when.

COLLEGE PARK, Md. — Imagine humans get eight years of warning that a large asteroid might be on a collision course with Earth. Could we do anything about it?

Right now, scientists don't know of any space rocks on track to cause serious damage to Earth in the foreseeable future. But if they spot one, they'd rather have a headstart in protecting people — so they're practicing by designing missions to a hypothetical threatening asteroid. The exercise is part of the International Academy of Astronautics' Planetary Defense Conference being held here this week.

For the exercise, NASA experts have designed a scenario in which scientists in March 2019 discover an asteroid that could impact Earth in April 2027. It's a fictional but realistic scenario, fully fleshed out so that scientists, engineers, policymakers and emergency-management experts can work through questions and concerns that might arise if scientists ever do identify such a threat.

And of course, a vital component of any response to such a situation is spacecraft. Space agencies would want to put together two different types of missions: first, reconnaissance projects that would get experts the data they need to evaluate the situation as confidently as possible and second, mitigation projects that could avert a disaster if it becomes clear such an action is necessary.

When it comes to the hypothetical scenario that planetary defense experts are playing out this week with simulation data, decisionmakers concluded pretty quickly that they wanted to start planning mitigation missions right away, even if these projects might later be scrapped if additional data clarifying the hypothetical asteroid's path concluded that Earth would be safe.

They also scrambled to send a reconnaissance mission out to get that data, and, as of the end of yesterday (May 1) in the conference — which simulates December 30, 2021, in the exercise — that mission had sent back enough data for scientists to be confident that the asteroid would impact Earth around Denver, Colorado. (Again, no need to panic about a fictional scenario.)

Needless to say, the world would prefer not to lose the Mile High City, so this reconnaissance data would mean humans have a little more than five years to execute missions to avert (hypothetical) catastrophe. It turns out that it's very difficult to knock an asteroid onto an entirely new trajectory instead, the key is to slow a space rock down or speed it up enough that it reaches the trouble point in its orbit before or after Earth has already been there.

On the timeline the scenario is investigating, with eight years between discovery and impact, planetary defense experts have two potential approaches. A kinetic impactor basically acts as a stumbling block: Put a large spacecraft in the asteroid's path the asteroid hits it and slows down just a little. If your impactor is large enough and catches the asteroid with lots of time to spare, you can delay the asteroid enough that it misses the disastrous 2027 collision with Earth.

But there's a hitch: given the details of the hypothetical scenario, humans would need to slow down the asteroid much, much more to save themselves than if they tried to speed it up instead. They aren't sure of the asteroid's mass yet, but its size — on the scale of 850 by 460 feet (260 by 140 meters) — suggests humans would need three separate stumbling blocks, and would likely want to send six in case of glitches.

Those spacecraft would need to launch around 2023 in order for Earth to emerge unscathed (and remember, in this scenario, that's just a year and a half away, and before scientists know the precise details of the object). Another cause for concern: If engineers go overboard on such devices, they could accidentally break the hypothetical asteroid into pieces, making Earth's risk much more difficult to understand.

There's a second type of mitigation mission — detonating a nuclear explosion above the surface of the asteroid, causing part of its surface to vaporize and the remainder of the space rock to recoil. This approach is also more adaptable to the many questions scientists still have about the hypothetical asteroid, like its mass and structure. The effect of a specific explosive device can be tuned, so to speak — detonate closer to the asteroid and the blast is stronger, detonate farther away and the effect is more gentle.

Fortunately, the NASA team working on the simulation exercise has an elegant solution — if at a staggering scale — to offer. First, build and launch (within just six months) two complex spacecraft that could fly out to the hypothetical asteroid and orbit it for several years. These probes would gather the information planetary defense experts need to modulate their attack of the space rock. Then, build and launch six missions to block the asteroid's path and slow it down, with the orbiting spacecraft monitoring that process. As a safety precaution, the team recommends, those two spacecraft could also be armed with nuclear devices: If, once scientists know all the details of the hypothetical space rock and its adjusted trajectory, they still aren't comforted, those explosive devices could polish off the job, should a global consensus to go nuclear arise.

Of course, no one wants to see this scenario unfold in real life. But by running the numbers and calculating the trajectories, planetary defense experts can be more confident that, if they do detect a real asteroid that poses a real risk, they can put together a plan.

## The warnings

There are generally two types of warnings: notification of a very close encounter and notification of a potential impact. For either of these, you'll know they're legitimate because "NASA has actually said something about it," said Johnson.

A close encounter means a space rock isn't going to strike Earth, but NASA thinks it's still deserving of the public's attention, explained Johnson. It could be as small as a 30-foot (10-meter) rock, or it could be something bigger like Apophis. Other people might spot the close encounter of the rock (as all known NEO trajectories are posted online) and then announce or publish news of the unsettling flyby earlier than NASA. But that's OK. The agency will take at least a few hours to verify such results.

"Our goal is not to be the first to announce something, but to be the ones that provide the best information available," explained Johnson.

If NASA detects a possible impact — something larger than around 30 feet across (10 meters) with a greater than one percent chance of hitting Earth — things get serious.

Johnson's office will give warning notifications to NASA to provide the White House, Congress, and government agencies. Public warnings won't simply be in the form of a NASA press release, tweeted out and posted online. "At that point the White House takes the lead on new information being released," said Johnson. "It becomes a national emergency event," he added. FEMA would have to prepare for a disaster if an impact on U.S. soil were likely.

NASA, however, won't be working alone. They'll share information with their close asteroid monitoring partners, like the European Space Agency and the UN-recognized International Asteroid Warning Network (IAWN). (For this story, scientists at the IAWN didn't comment, but suggested we speak with NASA's Johnson.)

"It becomes a national emergency event."

A crucial part of this process is telling the White House and other government leadership not only that an impact is likely (or possible), but what an impact will do. Many factors are at play, notably the size and composition of the object. "Will it detonate in Earth's atmosphere, or make it closer to the ground?" asked NASA's Johnson. "We can advise leadership as to what might be faced should the asteroid impact the planet."

The Tunguska rock, heating up as it traveled tens of thousands of mph through Earth's atmosphere, exploded. In stark contrast, a larger asteroid (some 100 to 170 feet wide) survived the atmospheric plummet and left a 600-foot-deep crater in Arizona 50,000 years ago. "A similar-size impact event today could destroy a city the size of Kansas City," David Kring, an impact expert at the Lunar and Planetary Institute, told NASA this year.

If it should pass that a sizable asteroid is destined for Earth, NASA astronomers and orbital modelers will run thousands of simulations, somewhat similar to weather or hurricane prediction, to forecast where it's likely to land. Fortunately, Earth is an ocean world, with seas covering 71 percent of the planet, so there's a good chance many rocks won't pummel land. (Though if a rock is big enough, it might not matter where it lands.)

Astronomers are finding these rocks. Taxpayer dollars are at work as NASA discovers about 500 asteroids over 460 feet wide — enough to cause at least major regional destruction — each year. (As of June 8, 2021, 9,677 of an estimated population of some 25,000 of these 460-foot-plus NEOs have been found).

Completing the survey is vital. In 2019, the "football field-sized" asteroid 2019 OK surprised astronomers. It zipped within some 40,000 miles of Earth.

## An asteroid that could wipe out a country will just miss Earth this week

##### By Matthew Rozsa
###### Published March 12, 2021 8:57PM (EST)

Asteroid passing earth (Getty Images)

### Shares

An asteroid the size of the Pentagon is headed our way.

The celestial passerby, named 2001 FO32, is expected to be the largest asteroid to approach Earth in 2021, measuring somewhere between 1,300 to 2,230 feet wide, according to NASA's Jet Propulsion Laboratory in California. The key word here is "approach" — this wide rock isn't going to actually hit Earth. But its close approach is a good warning that an asteroid of this size is guaranteed to hit Earth eventually.

2001 FO32 will be at its nearest on March 21. It is not expected to come any closer than 1.25 million miles to our planet — roughly 5.25 times the distance between Earth and the Moon — so there is no threat of it colliding with us anytime within the next few centuries. At the same time, it will come close enough for scientists to be able to get a good look at it. And while it won't be visible with the naked eye, amateur astronomers in the Northern Hemisphere with an 8-inch telescope or larger should be able to spot it in the early morning, when it will appear inside the Sagittarius constellation.

"By getting so close to Earth, it will be very bright in the sky," Dr. Tom Burbine, a senior research associate who studies asteroids at the Planetary Science Institute, told Salon by email. "It will be easier to get infrared spectra of the body, which allows us to estimate its composition. Radar observations can be done to determine its size and shape."

Dr. Henry Hsieh, who studies asteroids, comets, interplanetary dust and small satellites at Planetary Science Institute, said that it was an exciting chance to study an asteroid.

"The scientific significance of asteroids coming extremely close to Earth mean that astronomers can study them in much greater detail," Hsieh wrote to Salon. "Astronomers often study the composition of asteroids using spectroscopy, meaning they take the reflected sunlight from the asteroid and split it up by wavelength and search for signatures of various minerals. The closer an asteroid is, the brighter it will appear, and so the stronger the mineral signatures will be, meaning that astronomers can potentially get a really detailed picture of an asteroid's composition."

Want more science stories in your inbox? Subscribe to Salon's weekly newsletter The Vulgar Scientist.

Hsieh added that astronomers hope to learn more about how an asteroid's rotation and composition corresponds to its size. While that is usually difficult for smaller asteroids because they are so small, this one will be easier to observe because it will be brighter as it approaches Earth. In addition, "if asteroids get close enough, they can actually be studied by radar, i.e., by bouncing radio waves off of the asteroid which can give a highly detailed picture of the asteroid's surface."

Naturally, Salon was curious what would happen if 2001 FO32 actually did crash our planetary party and make a menace of itself, as happens every few million years. Such an impact would not be good for life on Earth, to be sure, but it would not cause a repeat of the type of extinction event that wiped out the dinosaurs.

"When talking about asteroid impacts, astronomers typically use the Torino scale for asteroid impact threats (similar to the Richter scale for earthquakes)," Hsieh explained, referring to charts that show what different numbers represent and how they are determined. Because 2001 FO32 is definitely not going to hit Earth, it rates at a zero on the Torino scale. If it was certain to collide with us, on the other hand, it would get a nine and cause what is known as "regional damage."

"This kind of damage would be roughly on the continent-wide or ocean-wide scale depending on where it hits, so in other words, it could potentially wipe out the US or Europe, or create tsunamis on all surrounding landmasses around the Atlantic or Pacific Oceans if it landed in the water," Hsieh explained. "The exact effects depend on the composition of the asteroid (i.e., if it's very fragile or more solid) and where it hits."

If an asteroid is fragile, it may explode in the air and create shockwaves that flatten all of the buildings and trees in a given area, such as happened in Russia in 1908. If a solid asteroid hit the ground in one piece, it would destroy a smaller area of land but throw up throw up a lot of debris that could cause air quality problems and harm agriculture. Should that same solid asteroid land in the water, it could also create debris clouds and would additionally result in tsunamis.

"Returning to the Torino scale and your second question, the threshold for a civilization-destroying impact is thought to be about 1 kilometer, so about twice the size of 2001 FO32," Hsieh told Salon.

Astronomers have gotten better at detecting asteroids near Earth. Indeed, in 2020, they detected a record number of asteroids passing our planet, identifying thousands of objects that were previously unknown.

Notably, this wasn't because there are more asteroids coming near Earth, but rather that detection technology has improved.

"I think the increasing number of detections of Earth-passing asteroids is entirely due to the fact that more asteroid search programs are going on with more telescopes dedicated to asteroid detection," Dr. William K. Hartmann, who among other things studies asteroids, comets, meteorites and small satellites at the Planetary Science Institute, wrote to Salon.

Correction: This article originally compared the distance between the asteroid and the Earth to Mars rather than the Moon. The author regrets the error.

### Matthew Rozsa

Matthew Rozsa is a staff writer for Salon. He holds an MA in History from Rutgers University-Newark and is ABD in his PhD program in History at Lehigh University. His work has appeared in Mic, Quartz and MSNBC.

The article in question has the correct answer:

Any NEO that is going to hit the Earth will swing near our planet many times before it hits, and it should be discovered by comprehensive sky searches like Spaceguard.

There are many all-sky survey projects that would likely detect any civilization-damaging asteroid. And if the survey projects detect such an asteroid, it is almost certainly the case that they would discover it many years prior to impact. More all-sky surveys with better and better detection techniques will be coming online in the next decade and increase our chances of spotting a potential impactor. As surveys increase, we can anticipate a rise in reports of "near misses" and "potential impact" stories, even though what will really happen is that our chance of being caught unawares is reduced.

So to put some numbers and references to the previous paragraph:

The Torino Scale describes asteroid impact hazards. To achieve "serious damage to our civilization," as specified in the question, would require a Torino Scale 9 or 10 impact. Such impacts occur on average every 10,000-100,000 years.

We already have all-sky surveys that are specifically trying to trace "Near Earth Objects" and potential impactors. These are finding NEOs at an increasing rate (and this is likely to continue), but most large NEOs have probably been found, as shown in this image:

(source: nasa.gov)

We're discovering fewer and fewer large NEOs even as we're discovering more and more total NEOs. This indicates that the chances of us having missed a "sneak" Torino Scale 9 or 10 asteroid are increasingly slim.

In combination with being an undiscovered large NEO, the doomsday asteroid would additionally need to be in an orbit that hits us quickly. That's highly unlikely: of the almost 10,000 NEOs detected to date, none has ever impacted. None is even anywhere near likely to impact.

The probability of a doomsday asteroid sneaking up on us is the product of small probabilities: the odds of us having missed a large NEO * the odds of it having a bulls-eye course.

In summary, although there are many, many asteroids out there, the vast majority of which are undiscovered, we benefit from an important fact:

Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.

## Comet could wipe out life on Earth with just six months’ notice, scientist warns

A PLANET-busting comet could crash into the Earth and wipe out humanity with less than six months' warning, a scientist has warned.

Astrobiology researcher Prof Lewis Dartnell says the intergalactic balls of ice and dust could be more dangerous to humanity than asteroids.

Speaking with the Daily Star, the respected author said comets are harder to spot than asteroids because they “come out of nowhere” from the outer reaches of space.

The University of Westminster professor added: “And because comets are falling in towards the sun from much further out, they come in much faster and that could potentially give us much, much less warning if one were to be on a collision course with the Earth.

“Potentially we could have as little as six months notice of a comet that is on its first orbit into the inner solar system on an Earth-crossing trajectory.”

Scientists currently only know about 20,000 potentially dangerous comets despite there being up to one BILLION of them in our solar system.

Typically, comets are made of frozen gas, rock and dust and release gas as they fly close to the sun – letting off gases and debris that give them a "tail".

The nucleus of a comet, dubbed “dirty snowballs”, can range from six to sixty miles wide.

Prof Dartnell's warning comes after a Nasa doomsday simulation earlier this month showed a city the size of New York would be wiped out if a space rock smashed into the Earth.

The test showed whether an international team of scientists and engineers could save the planet from a huge 1,000ft-wide asteroid.

The Nasa exercise has become a regular event among the world’s community of "planetary defence" experts who meet in Washington.

Two years ago a simulation just about saved Tokyo after the previous one wiped out Dhaka in 2015 and another in 2013 flattened the French Riviera in 2013.

The nightmarish scenario gave 200 astronomers, engineers and emergency response specialists a warning period of eight years.

### What's the difference between an asteroid, meteor and comet?

Here's what you need to know, according to Nasa.

• Asteroid: An asteroid is a small rocky body that orbits the Sun. Most are found in the asteroid belt (between Mars and Jupiter) but they can be found anywhere (including in a path that can impact Earth)
• Meteoroid: When two asteroids hit each other, the small chunks that break off are called meteoroids
• Meteor: If a meteoroid enters the Earth's atmosphere, it begins to vapourise and then becomes a meteor. On Earth, it'll look like a streak of light in the sky, because the rock is burning up
• Meteorite: If a meteoroid doesn't vapourise completely and survives the trip through Earth's atmosphere, it can land on the Earth. At that point, it becomes a meteorite
• Comet: Like asteroids, a comet orbits the Sun. However rather than being made mostly of rock, a comet contains lots of ice and gas, which can result in amazing tails forming behind them (thanks to the ice and dust vapourising)

But they failed to deflect ALL of the killer asteroids — roughly measuring 330 to 1,000 feet in diameter.

Initially they were working with a rough calculations that gave a one percent chance of slamming into Earth on April 29, 2027.

Each day during the conference new information emerged.

The teams then made decisions and awaited further updates from the organisers of the simulation game.

But ss fictional months ticked by, the probability of the giant space rock striking Earth rose to 10 percent before rocketing to 100 percent.

It was decided among the major space powers of the United States, Europe, Japan, Russia and China to build six “kinetic impactors” which would be fired at the asteroid to knock it off course.

Three of them managed to hit and deflect it — but a fragment broke off.

Washington considered sending a nuclear bomb to deflect the 200ft rock but this failed to happen because of political squabbles.

With two months before impact, it was confirmed New York would be destroyed.

The asteroid would enter the atmosphere at 43,000 mph before exploding 9.3 miles above Central Park in Manhattan.

The energy of the downward blast would be 1,000 times that of the nuclear bomb dropped on Hiroshima at the end of World War 2.

Everything would destroyed within a 9-mile “unsurvivable” radius, scientists said.

## Calculating its trajectory

Astronomers need long-term data to accurately determine the trajectory of asteroids and, as 2018 LA had just been identified, they didn't have much to go on.

Using what information was available, however, they were able to roughly calculate where it would enter Earth's atmosphere: In a swath stretching from southern Africa, across the Indian Ocean to New Guinea.

With more telescopes pointed at the asteroid, it became apparent that there may be an impact, Brown said.

By early Saturday evening local time (12:44 p.m. ET), there were reports of a fireball in the sky over Botswana, which lined up with calculations made by scientists. It was captured on webcams in the area as it lit up the sky.

Meteorites likely reached the ground as the asteroid broke apart, Brown said.

Only twice before has a small asteroid been detected hours before colliding with Earth. The first was 2008 TC3, which was detected 15 hours before it broke up over northern Sudan on Oct. 7, 2008. The second was 2014 AA, discovered only a few hours before it impacted over the Atlantic Ocean on Jan. 1, 2014.

And while 2018 LA was discovered shortly before it arrived at our atmosphere, there are numerous organizations searching for potentially hazardous asteroids (PHAs) that could seriously impact life.

Smaller objects are fainter and more difficult to spot in a large sky, though efforts like the NASA-funded Catalina Sky Survey are increasingly able to search a wider field of sky to find these somewhat elusive objects.

Asteroids are large debris left over from the formation of our solar system. Most are located in the asteroid belt between Mars and Jupiter, but occasionally some can get jostled out of their orbit, posing a threat to Earth.

According to NASA, however, about 90 per cent of all asteroids larger than one kilometre have been discovered.

Considering the short time available to scientists using telescopes around the world to track and calculate the impact of asteroid 2018 LA, Brown called the results successful.

"It's really tough to do," said Brown. "In general, Iɽ say the system worked pretty well."

## Asteroid Apophis Could Hit Earth. Here's How We Could Get to It First December 5, 2020 1:04 PM Subscribe

Hmm, if it were coming in January 2029 it could show up just in time for an inauguration after victory as a dark horse candidate in the 2028 us presidential election.

Going to go read the articles, but it would be cool to land a small craft on it in 2029, wait a couple years, and then push with a tiiiiiny bit of force to send it into a friendlier orbit.
posted by kaibutsu at 1:15 PM on December 5, 2020 [4 favorites]

I've been party to a couple of government exercises on the deflection of an asteroid (hypothetical scenario). And that has come up--that if you do nothing and it hits, it's an Act of God/Nature if you do deflect and it hits, you're probably on the legal hook now.

You don't get a lot of data except on relatively near passes to refine orbits either, so you get updates in bursts on a period of years. (They're just too small to observe clearly.)

(Another result that fascinated me was the general conclusion that, if you had a Chelyabinsk-sized impactor and you were sure it was going to hit, say, the rural U.S. plains, it's likely far more economical to evacuate and compensate

10,000 people and take the hit vs. staging a deflection mission. That was more like a

20m rock, for reference.)
posted by stevis23 at 2:00 PM on December 5, 2020 [11 favorites]

13th April 2029 is a Friday.

It's going to hit.
posted by Wordshore at 2:10 PM on December 5, 2020 [23 favorites]

The highest probability of impact is on April 12, 2068 and the odds of an impact on that date, as calculated by the JPL Sentry risk table using a March 2016 solution, are 1 in 150,000, but the nominal trajectory has the asteroid more than 1 AU (150 million km) from Earth on that date.

The odds of winning $1 million in the McDonald’s Monopoly game have been calculated as 1 in 451,822,158. posted by ricochet biscuit at 2:35 PM on December 5, 2020 [3 favorites] Coming in 2029: Elon Musk holds the Earth ransom. For what!? All of the bitcoin? A hit off of every DMT vape pen in the world? Open access to Area 51? The Arecibo site for a lair? A fresh new pair of khakis and the newest collector Yeezys? posted by loquacious at 2:43 PM on December 5, 2020 [12 favorites] The odds of winning$1 million in the McDonald’s Monopoly game have been calculated as 1 in 451,822,158.

This orbit would be easy to nudge into collision as well.

OK, nobody put Jerome P. Jacobson in charge of planetary defense.
posted by zamboni at 2:44 PM on December 5, 2020 [1 favorite]

Sadly, losing Aricebo makes the task of getting sufficiently accurate orbital data much harder.

I’m genuinely interested in how an unorientable (or barely orientable) radio telescope could be of use in detecting rogue near-earth objects, but Wikipedia says, without elaboration, that it has been. There are other telescopes at the facility, so it could be that those are involved instead?
posted by sjswitzer at 4:16 PM on December 5, 2020 [2 favorites]

I’m genuinely interested in how an unorientable (or barely orientable) radio telescope could be of use in detecting rogue near-earth objects, but Wikipedia says, without elaboration, that it has been

Coming in 2029: Elon Musk holds the Earth ransom.

For what!? All of the bitcoin? A hit off of every DMT vape pen in the world? Open access to Area 51? The Arecibo site for a lair? A fresh new pair of khakis and the newest collector Yeezys?

posted by ricochet biscuit at 5:25 PM on December 5, 2020 [8 favorites]

Radar. Arecibo was a pretty capable transmitter.

Just to clarify this a bit: as far as I know, Arecibo wasn't used to search for asteroids. When you're trying to detect a radar echo from millions of miles away, your only hope of getting a strong enough signal is to use a very tightly focused beam, so you have to already have a particular target in mind. But the radar signal allows you to take an approximately known orbit and measure it much more precisely, allowing for better long-term predictions.

Also, even though Arecibo's dish itself was fixed, the receiving equipment could be moved around the focal plane, allowing the telescope to be effectively steered by about 20 degrees in any direction away from vertical. Taking into account the Earth's rotation and axial tilt, and given Puerto Rico's closeness to the equator, anything reasonably close to the ecliptic was guaranteed to be observable at least some of the time.
posted by teraflop at 5:29 PM on December 5, 2020 [31 favorites]

I have viewed the historical documents many times

Surely, you don't think Gilligan's Island is a.
posted by stevis23 at 7:05 PM on December 5, 2020 [6 favorites]

I say we nuke it near orbit.

"Survival kit contents check. In them you'll find: one forty-five caliber automatic two boxes of ammunition four days' concentrated emergency rations one drug issue containing antibiotics, morphine, vitamin pills, pep pills, sleeping pills, tranquilizer pills one miniature combination Russian phrase book and Bible one hundred dollars in rubles one hundred dollars in gold nine packs of chewing gum one issue of prophylactics three lipsticks three pair of nylon stockings. Shoot, a fella' could have a pretty good weekend in Vegas with all that stuff."
posted by clavdivs at 7:23 PM on December 5, 2020 [12 favorites]

Note: if a cat shows up at your door asking to borrow a knife, give them one.

I feel like this is always true though
posted by Ray Walston, Luck Dragon at 7:54 PM on December 5, 2020 [17 favorites]

Surely, you don't think Gilligan's Island is a.

Those poor, poor people.
posted by Greg_Ace at 8:23 PM on December 5, 2020 [16 favorites]

The odds of winning $1 million in the McDonald’s Monopoly game have been calculated as 1 in 451,822,158. So you're saying there's a chance? posted by They sucked his brains out! at 8:25 PM on December 5, 2020 [3 favorites] I hadn’t known it was a radar as well as a telescope. It may help to reflect upon the difference between a telescope and a transmitter. posted by pwnguin at 9:07 PM on December 5, 2020 [3 favorites] Don't worry, the priests of Egypt have been preparing for this for thousands of years. Aziz, LIGHT! posted by kaibutsu at 10:56 PM on December 5, 2020 [12 favorites] Arecibo *was* a ginormous radar transmitter. *Now* it's a monument to hubris. Though 'giant rock from space may kill us all by surprise' might be reason enough to get it rebuilt, but with the general US attitude to science these days ¯\_(ツ)_/¯ posted by Absolutely No You-Know-What at 3:05 AM on December 6, 2020 [6 favorites] 2068? I'll be long since in the dirt by then. You young folks figure it out. It would seem to be in your interest. Ah. What many people feel about climate change. Ho hum I guess, the extinction of everything. Thanks for sharing! posted by tiny frying pan at 7:57 AM on December 6, 2020 [5 favorites] I also meant to mention that last week I saw a meteor fireball that was so bright and lasted so long that I went from gasping "Holy shit!" to "Ohhh shit!" and I was no foolin' waiting for visual signs of either a massive bolide explosion or impact. It was seriously the brightest, longest fireball streak I've ever personally witnessed, streaking across a major fraction of the visible night sky. It also seemed to be going slower than the usual meteor streaks I see, so I'm curious if I witnessed LEO space debris burning up or something. Ever since the all of the video of the Chelyabinsk bolide it's been etched into my brain that if I suddenly see new and very bright light with fast moving shadows I'm probably going to want to find shelter in a matter of seconds. posted by loquacious at 9:09 AM on December 6, 2020 [5 favorites] Ah. What many people feel about climate change. I can discern between a low probability event well beyond my lifespan and currently being one of the frogs in a pot that is slowly coming to a simmer. posted by jim in austin at 10:09 AM on December 6, 2020 [7 favorites] Ho hum I guess, the extinction of everything. The asteroid that wiped out the dinosaurs and most life on earth was 10 km (6 miles) across. This one is 370 m (1/5 mi), which is not nothing — if there is a collision, it would wipe out an area the size of Paris and kick up a fair bit of dust globally, I think — but it isn't quite the same, either. This app from Purdue and Imperial College may help with calculating future travel plans. posted by They sucked his brains out! at 10:26 AM on December 6, 2020 [4 favorites] Mi pensa im fong da belte. E₩e kin$ei thet @€%n!
posted by y2karl at 11:45 AM on December 6, 2020

Could we try to smash it into Mars, Venus or the Moo ? That would generate some useful scientific data and be extremely entertaining. Hitting Mars would seem to be more difficult or the two but we would probably get more data from a Martian impact. The moon would be even more observable but might be too risky. Still imagine the watch party for the great lunar collision.
posted by interogative mood at 3:01 PM on December 6, 2020

I feel like moon impact would be pretty risky. Seveneves?

It has no where near the mass required to break the moon. The bigger risk is they you miss and it attempts to lilthobreak on Earth instead.
posted by jmauro at 10:39 PM on December 6, 2020

I don't think this one would make all life go extinct, but can it least get rid of McRib once and for all?

Not a chance. McRib finds a way.
posted by srboisvert at 6:01 AM on December 7, 2020 [7 favorites]

I dunno. An asteroid, Apophis, and the imminent end of the world? This is a Richard Dean Anderson problem.

"It's 'O'Neill', with two L's. There's another Colonel O'Neil with only one L, and he has no sense of humor at all."
posted by TheHuntForBlueMonday at 7:21 AM on December 7, 2020 [6 favorites]

So a question I've been wondering about.

It's possible to design a nuke so it produces more radiation in a particular range, thus the famous neutron bomb.

Shouldn't it be possible to build four really big nukes tuned to release as much radar frequency radiation as possible? Send two up orbit by 30 degrees and the other two down orbit 30 degrees. Set one off at each location, wait 48 hours and set off the final one at each location.

Basically using nukes as giant radar flash bulbs to build a stereo Doppler picture of the solar system.

Would that produce anything really useful, or do we already have all the data it might give us without, you know, sending four big nukes into space?
posted by sotonohito at 10:55 AM on December 7, 2020 [2 favorites]

I don't think this one would make all life go extinct, but can it least get rid of McRib once and for all?

A civilization-threatening asteroid would just make the spot and future prices for pork plummet, ensuring that the McRib would be the only thing that McDonald's served right up until the moment of impact.
posted by loquacious at 11:06 AM on December 7, 2020 [3 favorites]

Would that produce anything really useful, or do we already have all the data it might give us without, you know, sending four big nukes into space?

Let's pretend that we can do this for a moment. So we have our tuned nukes or nuclear powered or chemical microwave lasers (err, MASERs) or whatever, and we're able to flashbulb our solar system and irradiate the entire solar system in some way that isn't drowned out by the sun and also doesn't irradiate the earth with, say, harmful amounts of gamma, x-rays or neutrinos.

Now, how do we detect, collect and image all of that massive amount of data all at the same time?

Even if we mined or seeded the solar system with millions of detectors and a massive deep space relay network, how do we record, collate and process all of that data all coming in basically at once, or in whatever staggered relativistic time frames that would equate to - at maximum about a one or two light-days?

Ok, lets assume we've collected all of that data, or enough of it. It's now one of the largest single aggregates of data in the history of humanity.

We now know where everything was at the moment of the blasts and illumination. We have now have one historical picture of where everything was at that moment.

Where are those objects now?

Ok, so we do a second blast and data capture. Now we know roughly where all of the objects were in two places and a general idea of their trajectory and where they were going. We're crunching all of those numbers.

How much math and computer time is that? How do we store and process that much data in time for it to be useful without consuming every available joule of electrical energy? How do we even build data and computing centers that big without rapidly accelerating global warming or simply co-existing as a species with a project this big?

But wait, it gets even worse! Now our data is out of date and inaccurate, and orbital mechanics and physics being what it is, lots of our projections are now wrong and we can clearly see individual objects are not where they're projected to be!

So we do a third shot, and a fourth, and a fifth, and so on, but now we have so much data we can't really handle it. Projecting interactions between solar objects is getting more and more complicated, so we add even more processing power and power consumption, most of our planet and infrastructure and available power is running full tilt and projecting orbital mechanics and things are getting really toasty down here on Earth.

We've automated our basic needs and something like 99% of humanity is dedicated to the science of looking at space rocks and trying to figure out if they're going to hit us or not, yet our planet now resembles a mix between the global city-state of Star Wars' Coruscant and the nightmare hellscape of Dune's Geidi Prime with a touch of Ix.

And we still can't accurately model or project all of these objects. Because physics are chaotic and Newton is only mostly right at a certain macro scale.

But we plod onward and upwards, achieving a Type 1 or Type 2 civilization. We have most of the energy available in the solar system being harvested and utilized for computing. The core of our planet has been entirely replaced by quantum-optical computing. Our temperature is relatively stable. Waste heat is harvested and recycled with 99.99999% efficiency.

We know where a majority of the orbital bodies larger than a boulder in our solar system are all the way out to the Kuiper Belt and heliosphere, where they're going, where they interact with each other down to a level of detail we can predict when very small rocks will collide with other very small rocks, and we can model where they will be after they collide. We're now playing solar chess like a Grandmaster, thinking and projecting dozens and dozens of moves ahead on the solar system or galaxy's largest, most complicated chess board.

Except the models still don't match reality. Our calculations and projections are still being thrown into disarray with details as small as a grain of sand, the texture or density of a colliding set of objects and even the details of the shape of each orbital object - because none of these objects are "perfectly spherical cows" or whatever.

Very small details keep wrecking our projections and we're now continuously trying to measure the length of England's coastline over and over again as the tides change and waves keep splashing over our proverbial yardsticks.

At some point in this timeline we keep pushing. We simply must know where everything is. Our observational, detection and projection technology is so advanced that we're now counting trillions of trillions of pebbles and grains of sand. There's so many computational photons and electrons bouncing around our global circuits that they now represent a fractional mass of our dear planet.

And seriously weird, spooky shit starts happening, like physics is laughing at us - because it is. Our intense levels of observation seem to be warping what we know and consider to be reality. Even our attempts at illuminating, detecting and observing our solar system are now pushing grains of sand and dust around and altering their trajectories, which then wreck the accuracy of our predictions more and more.

At some point in this projected future suddenly the Earth and likely a massive part of the solar system starts to implode under its own informational and photonic weight, and a few very smart people realize just a few moments too late that we've accidentally created a kugelblitz or the orthogonal opposite of a black hole - a white hole, composed entirely of too much energy or information in too small of a space.

And just like that we cross a threshold of energy and information density and we simply vanish in a puff of logic.

This is our universe. Newtonian physics don't really exist. There isn't really any such thing as a straight line.

Our precision in measurement is now so fine and accurate that even the endless ripples of gravity waves sourced from all over our observable universe are now observably, minutely distorting measurement standards. A meter is more or less of a meter depending on when and where we measure it. A second is sometimes more or less than a second. A kilogram is more or less than a kilogram.

Go outside and look at the night sky and think about our little dust mote of a planet spinning and wobbling through a nearly empty sea of chaotic nothingness. Point a laser pointer up at the stars and wave it around, and try to imagine that it's not an impossibly straight beam, but a garden hose spraying curves of water with every tremble of your hand, the beam sweeping with the spin of the Earth, sliding along on it's orbital track around the sun as your trembling hand tries to hold the laser perfectly still from your frame of view.

Even the 25,000-ish year wobble of the Earth's precession is recorded in that beam. Even your own heartbeat and breath is there in that wobbling, spraying stream of photons. Every atmospheric distortion, every bit of Brownian motion of the molecules and atoms in our atmosphere. Every gravitational pull of the sun itself down to every grain of sand and dust is bending and distorting that stream of photons.

And yet. we still can't measure it accurately, not without changing the measurements themselves.

Feel free to go at least a little bit gibbering mad at this point. I know I do when I try to ponder these things. Space isn't just really big, it's totally stark raving bonkers.

At some point far back at the beginning of this thought exercise it becomes apparent we should have just built a bunch of lasers or missiles to shoot down any threatening objects as we detect them approaching us. Or even better, gone out and harvested this matter to make an orbital ring. Or a Dyson sphere or swarm.

At least that way we'd have an idea of where it is if we go out and nail it all down and build spacecraft out of it all.

Alternatively? Don't panic. Enjoy the ride.
posted by loquacious at 12:13 PM on December 7, 2020 [19 favorites]

Would that produce anything really useful, or do we already have all the data it might give us without, you know, sending four big nukes into space?

I think it's a great question! The principles of radar gives a lot of hints on where there might be real problems.

Energy decreases as an inverse-square both on the way out and the way back from hitting an object, and overall decreases as the /fourth power/ of the range. The usual way to deal with this is by using a directed beam. Which also helps cut down a lot of the information processing needed, but increases the number of pings needed to get a good overall picture. Still, that inverse-fourth-power is going to be a real problem: If you double the distance, you get 1/16th of the signal coming back.

The object is also going to absorb a lot of energy, especially if it's non-metallic (say, coated in lots of regolith, like an asteroid). It does look like there's a fair amount of iron in the lunar regolith (made of broken asteroids), but probably still rather less radar reflective than (say) an airplane hull. Again, this bumps up the energy needed.

But this all comes down to a concrete question of how much energy you get out of the nuke, and how far that lets you see. At some distance, the signal strength will drop to the level of the cosmic background noise in whatever frequency you're working with that's your maximum observable distance. And as mentioned, less-reflective rocks will only be apparent at much shorter distances.

I think I'm a bit happier on the computational side than Loquacious: We already track everything bigger than Xmm in near earth orbit, and that's a LOT of space junk. You presumably just don't care about space rocks below a certain radius, which cuts down the compute needed by a large factor by ignoring all signals below a certain strength/time threshold. Presumably we're only looking for pretty big rocks we haven't been able to detect by other means already getting a neighborhood and rough velocity may be enough to help find the objects via telescopes and ensure that they're not on a collision course, without requiring more floodlights.
posted by kaibutsu at 5:37 PM on December 7, 2020 [3 favorites]

Also, on a practical level, while it'd be kinda nice to know where every rock bigger than, say, 10 meters, is going to be a thousand years from now, mostly what I'm worried about are where rocks big enough to do serious damage will be in 10ish years.

Presumably if we know a rock will hit us in 10 years we can send out a robot with a booster, have it hook on and nudge the rock a bit, and then it won't hit us. I mean, with a 10 year timeframe even adding a tenth of a millimeter per second on any random vector will move it 30,000km out of the way.

Doesn't make as good a movie as Bruckheimer's, but it'd work.
posted by sotonohito at 4:10 AM on December 8, 2020 [1 favorite]

Presumably, yes, but it will be difficult to know with certainty what the impact percentage (or even point on the planet) would be that far out. That's going to make it difficult to muster the will to spend interplanetary booster money on such a project.

The Office of Planetary Defense at NASA has their exercise reports up under "Supporting Documents" (The 2014 exercise was the one I participated in.) Go to Figure 3 to see a years-out "risk corridor"--it's halfway around the globe.

And don't forget there's uncertainty in the object's mass as well that adds uncertainty to how much of a nudge you need. (If you really give yourself 10 years, you can probably design for 120% of maximum estimated displacement needed or something, but it factors in.)
posted by stevis23 at 5:12 AM on December 8, 2020 [3 favorites]

I think I'm a bit happier on the computational side than Loquacious: We already track everything bigger than Xmm in near earth orbit, and that's a LOT of space junk.

And we still don't see all of it all the time. Small debris strikes on the ISS/Zarya and other orbital objects are very common.

We know where a lot of that stuff is because we either put it there and we knew where it was or it's been very recently seen, recorded and plotted via radar.

Even with the intense amount of space debris we do have, it's still much less numerous or massive than the rest of the solar system. A significant portion of the total mass in our solar system might actually be objects that are asteroid sized and much smaller. If we take into account the Kuiper Belt and Oort Cloud and everything else it may likely exceed the mass of all the known proper planets put together - perhaps even including the sun.

Detecting, plotting, tracking and updating the orbital ephemera for these LEO and NEO debris objects is orders of magnitude easier than doing the same thing for the whole solar system. This debris doesn't have a quantifiable gravity well like a large asteroid or planetoid, and the orbits are relatively simple.

I was mostly kind of joking about the totally hyberbolic computational loads - but this was a humorous response to the proposal trying to accomplish this with a series of "flashbulb" events and trying to describe how damn difficult and wobbly it is to get even basic LEO orbital calculations to accurately predict reality with so little data, much less the entire solar system.

Even right here on Earth we have to deal with gravitational anomalies with satellites and debris in LEO simply because the Earth is very lumpy, especially inside where it's kind of gooey and moving around, so projecting where a satellite or a given piece of debris should be in a month or a year is only so accurate.

And, yep, the real answer is just to build better detection and tracking equipment. It'd be cool if we had like a hundred or a thousand Arecibo style dishes all over the world. It sure would make finding any of these rocks a lot easier and give us a lot more warning time.
posted by loquacious at 9:48 PM on December 9, 2020 [1 favorite]

« Older Spandex is a right, not a privilege. | a delicate balance. Newer »

## SHOCK ASTEROID WARNING: Planet earth faces 100 YEARS of killer strikes starting in 2017

A previously unknown asteroid belt has been located in deep space and is now hurtling towards our part of the solar system.

It means a 'global killer' could collide with Earth as soon as 2020, wiping out life as we know it and changing the climate for millennia.

The terrifying predictions came as NASA revealed disturbing new data showing 400 impacts are expected between 2017 and 2113, based on new observational data of objects seen in space over the past 60 days.

Most will have a maximum diameter of around 100 metres - the size of seven double decker buses - and the potential to cause significant damage.

But concerned scientists warned a colossal "monster" is also heading our way, with one 'mega' asteroid threatening earth in just SIX years.

### Radar Image of Asteroid approaching Earth

It follows claims this week by physicist Professor Brian Cox that a bus-sized asteroid, named 2014 EC, came within 61,637 kilometres (38,300 miles) of Earth in March.

He said there is an "asteroid with our name on it" and it is only a matter of time before an asteroid large enough to wipe out the human race collides with Earth.

Many believe an asteroid was responsible for killing the dinosaurs with a similar life-changing event potentially just around the corner.

Professor Bill Napier, an astronomy expert at the University of Buckingham, said a strike by either an asteroid or debris from a comet could have devastating consequences.

He said: "If something like this happened, depending on where it hit it would be absolutely life-altering.

"The atmospheric chemistry would be upset by cutting out sunlight. It would be like a nuclear winter and could last for tens of thousands of years.

"These comets are 200-300km (186 miles) in diameter they are sheer monsters and could sterilise the earth if we are hit by one.

"The more immediate risk comes from sub-kilometre (smaller) asteroids and there are tens of thousands of these in space which are quite capable of causing damage on a regional scale.

"One hit Siberia in 1908 and luckily it was not in a populated area. Had this happened in London it would have wiped out everything within the M25 and you would have heard the collision in another country."

And experts warned of the possibility of something much bigger striking earth in 2020.

Asteroid 2012 DA14, discovered by astronomers at the LaSagra Observatory in Spain, currently has less than a one per cent chance of hitting but scientists can't rule out the possibility that it might smash into our planet.

Paul Chodas, a planetary astronomer at NASA's Jet Propulsion Laboratory (JPL) said: "The orbit for 2012 DA14 is currently very Earth-like, which means it will be very close to Earth on a regular basis."

Professor Napier said the earth is at risk of two types of strike - asteroids, which are lumps of rock, and much larger comets formed from ice which shatter into billions of "diamond-like" pieces as they hit the earth.

He said though some famous comets like Halley's Comet present little risk there are similar ones out there which could have catastrophic effects.

The Swift-Tuttle Comet, discovered in by Lewis Swift on July 16, 1862, and by Horace Parnell Tuttle on July 19, 1862, is next due to rocket past the planet in the year 4479.

Professor Napier said: "Halley's Comet, which is about 10km across does not cross closely enough to the earth, the most dangerous one is the Swift-Tuttle Comet which is 27km across and passes very close to the Earth.

"There is a more immediate risk from the smaller asteroids.

"Comets are extremely fragile ice bodies and from time to time they get caught up in the gravity of the giant planets and are thrown inwards, this stress can cause them to disintegrate.

"The dust would cut out the sunlight and we would see multiple bombardments.

"This is not unlikely at all, and if we are looking at small comets, they become a significant risk on time scales relative to civilisation and capable of collapsing civilisation.

"These things are floating around in the sky and there is a real hazard out there that hasn't been properly studied, and it could happen at any time.

"Needless to say there's a lot of controversy around the subject."t could be tomorrow.

Professor Cox, 46, said when 2014 EC sideswiped the Earth a few months ago it came dangerously close to wiping us all out.

He said: "We didn't see it, we saw it on the way out, but if it had just been a bit further over it would have probably wiped us out. These things happen.

"The thing that bothers me about that is we do know how to do something about it.

"There is an asteroid with our name on it and it will hit us."

According to the JPL there are more than 100 "ring-like" structures on Earth which could have been caused by an impact.

A working group chaired by Dr. David Morrison at the NASA Ames Research Centre, estimates there are more than 2,000 asteroids larger than one kilometre (0.6 miles) across in space.

NASA says an impact by one of these "in the wrong place" would be a catastrophe, but it would not threaten civilisation.

The working group warned an impact by an asteroid larger than 1-2 kilometres could throw the climate into chaos triggering crop failure and loss of life.

An impact by an object larger than about five kilometres is damaging enough to cause mass extinctions, it said.