Astronomy

What would a 220km diameter asteroid impact do to Earth?

What would a 220km diameter asteroid impact do to Earth?


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I was looking at this chart,

which shows that an order of magnitude increase in asteroid impactor diameter roughly corresponds with two orders of magnitude increase in it's rarity. So if the K-T Impactor at 10km diameter is a 100 million year rarity impact, then a 100km diameter impact has a 10 billion year rarity (on the order of the lifetime of our planet). On a large time scale, orbital perturbation allows for some chaotic orbits, so it might not be vanishingly likely that one of the big asteroids eventually hit earth. The asteroid 16 Psyche orbit overlaps in distance to the sun with Ceres, so it could potentially get a natural gravity assist into another orbit.

What would happen to Earth if it got hit by the asteroid 16 Psyche at, say, 40 km/s in the Pacific off the coast of Japan?

I am specifically looking for an answer to one or more of the following questions: How big would the crater be? How much kinetic energy would be released? What portions of that would be transferred into heat, ejecta, and deformation? Would there be a secondary antipodal mountain formation like the Caloris impact on Mercury? Would it cause magma oceans? Would life on earth survive to reclaim the surface before the Sun went red giant?


Using the impact effects calculator

The energy before impact (making a some reasonable assumptions) is $3.35 × 10^{27}$ Joules = $7.99 × 10^{11}$ MegaTons TNT, most of which would be deposited in the Earth.

The impact effects calculator doesn't discuss the formation of antipodal mountains (this is not a well-understood process) but it certainly seems possible that there could be major antipodal effects. The initial crater would fill with lava, but there would not be a planet-wide magma ocean.

Would life survive? perhaps, life is surprisingly resiliant. This would cause mass extinction, and probably wipe out much or all of complex life. But "until the sun expands to a red giant" gives us millions of years for evolution to find a way. But any answer would have to be speculative.

The average interval between impacts of this size is longer than the Earth's age.


What Can We Do If an Asteroid Threatens Earth? Europe Starts Planning

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. [Potentially Dangerous Asteroids (Images)]

"These include the size, mass, speed, composition and impact angle," he added. "Nonetheless, this shouldn't stop Europe from developing a comprehensive set of measures that could be taken by national civil authorities, which can be general enough to accommodate a range of possible effects."

The 2013 Russian meteor explosion, which occurred above the city of Chelyabinsk, helped to bring the asteroid threat into a new realm of public awareness. The shockwave created by the airburst injured 1,500 people the vast majority were cut by shards of flying glass after windows were shattered.

The European authorities performing the new simulation, which took place in late November, took a lesson from the Chelyabinsk event, determining that it would be best to warn the public to stay away from windows and stay in buildings' most secure areas — similar to the advice given during tornadoes.

Officials considered what to do if Earth were threatened by an object between 39 feet and 125 feet wide (12 to 38 m) traveling at 28,000 mph (45,000 km/h). ESA and related warning agencies would need to work quickly, they determined, and coordinate with civil protection authorities to give information about where and when the asteroid would likely strike, and what effects would be anticipated.

"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," Gerhard Drolshagen, of ESA's near-Earth-object team, said in the same statement. "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."


NASA asteroid WARNING: Giant ONE MILE wide asteroid will skim the Earth before Christmas

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The giant asteroid will reach its closest possible distance to Earth just three days before Christmas, in the wee hours of December 22. NASA&rsquos scientists at the Jet Propulsion Laboratory (JPL) expect the space rock, dubbed Asteroid 2003 SD220, to swing by around 1.04am GMT (UTC). The asteroid measures somewhere in the range of 3,018ft to 1.3 miles (920m to 2.1km) in diameter. Hundreds of tonnes of space debris slam into the planet on a daily basis but are stopped by the Earth&rsquos atmosphere.

Related articles

A rogue asteroid on this scale would pass through the atmosphere unscathed and claim millions of lives if it ever struck the Earth.

According to Dr Bruce Betts of The Planetary Society, an asteroid this large would cause &ldquoregional destruction&rdquo or even a &ldquoglobal catastrophe&rdquo.

The space expert said: &ldquoUsing the cut-off for asteroid diameter of one meter, there are estimated to be more than half a billion near-Earth asteroids.

&ldquoFor objects that cause major damage if they hit Earth &ndash larger than about 30 meters) &ndash there are about a million. So far, we are approaching 20,000 found.

NASA asteroid warning: A monstrous asteroid will approach the Earth on December 22 (Image: GETTY)


No, An Asteroid Is NOT Going to Hit Earth in 2106

[Note: At 19:00 UTC (2:00 p.m. Eastern US time) today, Wednesday, Feb. 13, I will be doing a live video chat with astronauts Ron Garan and Ed Lu on Google+. Ron is with Fragile Oasis, and Ed with the B612 Foundation, and both have a motivated interest in the prevention of asteroid impacts. Don’t we all? And that’s why we’ll be talking Apophis, 2012 DA14, and what we can do if we should see an asteroid with our number on it. I hope to see y’all there!]

On Friday of this week, a small asteroid about 50 meters across will miss the Earth by a mere 27,000 kilometers. 2012 DA14 was only discovered last year, but it didn’t take long to see that it would have a close, but definitely not too close, encounter with Earth this year.

Ironically, within hours of posting an article about DA14 I got word from readers about another asteroid. An article is going around the web this rock is going to hit us…in the year 2106.

The article, originally posted on The Voice of Russia and reposted on Space Daily, is a fascinating mix of fact and error. A lot of what it says is accurate, but the most important claim—that an asteroid will impact Earth in 2106—is simply wrong.

I won’t mince words. The headline of the article, “We have 93 years left till the next End of the World: killer asteroid to hit Earth in 2106”, is appalling. It’s fear-mongering, plain and simple, because it’s totally wrong.

So let me be clear, where the article is not: The asteroid in question is real, and it does sometimes approach the Earth, but the odds of an impact in 2106 are so small that they are indistinguishable from zero.

In other words, rest easy. Or more accurately, don’t worry about the fate of your grandchildren just yet. Here’s the deal.

The asteroid is called 2012 YQ1, and it was discovered (as you might tell from its name) in 2012. Its size isn’t well known, but it’s probably in the 100-200 meter range, bigger than an American football field. It travels around the Sun on a highly elliptical orbit, taking just under three years to orbit once. Its orbit stretches from the inner solar system, between the orbits of Venus and Earth, out to as far as halfway to Jupiter. YQ1’s orbit is tilted a bit with respect to ours, but the geometry lines up in such a way that once per revolution the asteroid has the potential of approaching pretty close to Earth.

It last passed us in January 2013, staying a comfortable 15 million km (9 million miles) away—a huge margin, 35 times the distance to the Moon. No big deal.

All well and good. But, according to the article in Voice of Russia, when it was discovered the astronomers projected the orbit well into the future, and found it will impact Earth in January 2106.

Aiiiieee! Are we all doomed?

No. The claims of an impact are at best exaggerated.

When the asteroid was found, only a handful of observations of it were made, and only using a single telescope. This is fine for a discovery announcement, and even if you want to predict the position of the asteroid for a few days or weeks, so other astronomers can follow up and observe it themselves.

But trying to project the orbit of an asteroid like this too far in the future starts getting difficult. Any small uncertainty in the initial measurements get amplified as you project the position into the future, making its predicted location murkier and murkier. Eventually, it gets so fuzzy you can’t make any claims at all.

Think of it this way. Imagine you’re an outfielder in a baseball game. You see the pitcher throw the ball, and the batter swings. It’s a hit! But one-tenth of a second after the batter makes contact, you close your eyes.

Now, based on the fraction of a second you saw the ball move, can you catch it?

I would be willing to bet a lot of money you won’t. You weren’t able to watch the ball long enough to get a good fix on its direction, its speed, its position. It could land next to you, or it could fall 40 meters away, or it could be knocked right out of the park.

The only way to catch it would be to keep your eyes on it, observe it as long as possible until you can be completely sure of where its headed.

The same is true for asteroids. Observing one for a few days is not nearly enough to be able to get accurate predictions for a century in advance. You have to observe it over a longer period of time and nail down those uncertainties if you want to have any hope of knowing where it is in the future. Even after a year you probably won’t have enough observations to make long-term predictions.

Claiming an asteroid will impact us in 96 years after observing it for a week is, quite simply, impossible. The best you can do is determine the probability of an impact. Back to the baseball analogy, imagine you could only guess the ball’s direction to within a few degrees after it left the bat. At that distance, that small uncertainty in direction adds up to a lot of uncertainty in its position when it reaches you. You could be off by ten meters or more to the left or right, in or out. That’s a big area. How much of that area is covered by your mitt? Not much. Your odds of catching the ball by chance are maybe one in a thousand.


Collisions in the Solar System 531 Case Study Meteor Crater Arizona

On Earth, a meteor impact occurred 50,000 years ago, a crater 180 m deep with a rim rising 30-60 m above the surrounding plain and a diameter of 1,200 m was formed. This crater is known as the Meteor crater or as Barringer Crater (see Fig. 5.6). Kring [130] calculated magnitudes of pressures and wind velocities as a function of distance for that event. He assumed two cases for the energy that was set free: 20 megaton and 40 megaton. For comparison, the Hiroshima bomb had only 15 kt equivalent energy, thus, the energy released through the impact corresponded to at least 1,000 Hiroshima bombs. The results are given in Table 5.2.

It can be roughly estimated that the devastated area around Meteor Crater was about 800-1500 km2. Let us take as a mean value 1,000 km2 and estimate the chances of it being in these 1,000 km2 compared to the total surface of the Earth which is 510 x106 km2. This is 1:500,000. It also can be estimated that the probability of such an impact is 1:1,500, which means that it can occur on an average every 1,500 years. Then, the combined probability for a person standing in the right area at the right time, that is, being killed by an impact that lead to the Meteor Crater is 1 in 7.5x 108.

In Fig. 5.7, the approximate frequency of impacts vs. megatons TNT equivalent energy is given: for example, in every decade, an event with an approximate equivalent energy of

1 megatons has to be expected. The impact effects of the Meteor Crater event affected only about 1,000 km2 and no global extinction resulted. From this Figure, it can be deduced that an impact of 104 megatons TNT equivalent would

lead to a global catastrophe. The marked events (Tunguska and K-T impact) will be discussed below.

Let us do another example for the calculation of the probability that a person could be killed due to an impact event.5 A 105 megaton impact certainly would lead to a global catastrophe and such an event could be expected every 5 x 105 years. Let us assume that one in four people would be killed in such a global catastrophe. Then, the chances for any person dying in such an event during the next year is one in two million.6 The diameter of a crater that such an object would cause is between 10 and 20 km.

6 The chances of being killed in a car accident is about 1 in 5,000.

1/100 1 100 1 04 1 06 1 08

Megatons TNT Equivalent Energy

Fig. 5.7 Approximate frequency of impacts vs. megatons TNT equivalent energy (adapted from [130])

1/100 1 100 1 04 1 06 1 08

Megatons TNT Equivalent Energy

Fig. 5.7 Approximate frequency of impacts vs. megatons TNT equivalent energy (adapted from [130])

5.3.2.1 Evidence for Impact Theory

Sixty-Five million years ago, about 70% of all species on Earth disappeared within a very short time. This mass extinction is known as the K-T event because it occurred at the Cretaceous-Tertiary border in the Earth's history. In a layer near Gubbio, Italy, Alvarez, Asaro, and Michel [1] found a peculiar sedimentary clay layer (only 1 cm thick) that was deposited at the time of a mass extinction event moreover, this layer contained anomalous amounts of the rare element iridium. It can be easily explained why that element is rare on Earth. At the early stage of Earth formation, heavy elements like iridium, platinum, or iron sank down to the core when the Earth was largely molten (differentiation process, see planetary formation). Such a differentiation process did not occur on the small bodies of the solar system such as meteoroids or asteroids. These objects still have the primordial solar system composition. To explain the Ir abundance and other element anomalies found in that layer, the impact of a 10 km chondritic asteroid would have been sufficient.7 Such a large impact would have had approximately the force of 100 trillion tons of TNT, i.e., about 2 million times as great as the most powerful thermonuclear bomb ever tested.

7 Under the assumption that it contained the normal percentage of iridium found in chondrites.

The impact theory can also be traced back to M. W. DeLaubenfels' hypothesis [50].

Summarizing, the Alvarez impact theory is supported by several observational facts:

• Chondritic meteorites and asteroids contain a much higher iridium concentration than the earth's crust because they have about the same concentration of iridium as the whole earth and were not differentiated.

• The isotopic composition of iridium in asteroids is similar to that of the K-T boundary layer but differs from that of iridium in the earth's crust.

• Chromium isotopic anomalies found in Cretaceous-Tertiary boundary sediments also strongly support the impact theory and suggest that the impact object must have been an asteroid or a comet composed of material similar to carbonaceous chondrites.

• Shocked quartz granules, glass spherules, and tektites are common, especially in deposits found in the Caribbean area.

• All of these constituents are embedded in a layer of clay, which can be interpreted as the debris spread all over the Earth's surface by the impact.

While the element anomaly was the first evidence of an impact event that led to the mass extinction, the question remained as to where on Earth this impact did occur. In 1990, Hildebrand and Boyton [102] became aware of data by geophysicists that were searching for oil in the Yucatan region of Mexico. They found a 180 km diameter ring like structure named Chicxutub crater. Using the 40Ar/39Ar method, the age of the crater was determined to be 65 million years.

Schuraytz et al. [220] found Ir anomalies even in subsplits of melt rock and melt breccia from the Chicxulub impact basin.

Several other craters appear to have been formed at about the time of the K-T boundary. As it has been observed during the Shoemaker-Levy 9 impact on Jupiter, an asteroid could fragment before its collision, therefore, the craters found were impacts of a larger body that fragmented before collision with the Earth. The craters (apart from the Chicxulub crater) that have been found are

1. Boltysh crater (24 km diameter, 65.17 ± 0.64 Ma old), Ukraine.

2. Silverpit crater (20 km diameter, 60-65 Ma old) in the North Sea.

3. Eagle Butte crater (10 km diameter, <65 Ma old) in Alberta, Canada.

4. Vista Alegre crater (9.5 km diameter, <65 Ma old) in Parana State, Brazil.

5.3.2.2 Mass Extinction During the KT-Event

The biological system is quite complex and the extinction of one group inevitably leads to extinction of other groups.

The K-T impact caused a major change in both marine and land ecosystems. Before the K-T extinction, about 50% of known marine species were sessile, and after it, only about 33% were sessile. On land, the dinosaurs became extinct, therefore, mammals were able to become the dominant land vertebrates this seems important, also, for human evolution.

In North America, as many as 57% of plant species may have become extinct. The Paleocene recovery of plants began with a "fern spike" like that which signals the recovery from natural disasters (e.g., the 1980 Mount St. Helens eruption). The effects were quite different for different organisms. Some trends can be stated:

• Organisms that depended on photosynthesis became extinct or suffered heavy losses - from photosynthesizing plankton (e.g., coccolithophorids) to land plants. And so did organisms whose food chain depended on photosynthesizing organisms, e.g., tyrannosaurs (which ate vegetarian dinosaurs, which ate plants).

• Organisms which built calcium carbonate shells became extinct or suffered heavy losses (coccolithophorids many groups of molluscs, including ammonites, rud-ists, freshwater snails, and mussels). And so did organisms whose food chain depended on these calcium carbonate shell builders. For example, it is thought that ammonites were the principal food of mosasaurs.

• Omnivores, insectivores, and carrion-eaters appear to have survived quite well. At the end of the Cretaceous, there seem to have been no purely vegetarian or carnivorius mammals. Many mammals, and the birds which survived the extinction, fed on insects, larvae, worms, snails, etc., which in turn fed on dead plant matter. So, they survived the collapse of plant-based food chains because they lived in "detritus-based" food chains.

• In stream communities few groups of animals became extinct. Stream communities tend to be less reliant on food from living plants and are more dependent on detritus that washes in from land. The stream communities may also have been buffered from extinction by their reliance on detritus-based food chains [225].

• Similar but more complex patterns have been found in the oceans. For example, animals living in the water column are almost entirely dependent on primary production from living phytoplankton. Many animals living on or in the ocean floor feed on detritus, or at least can switch to detritus feeding. Extinction was more severe among those animals living in the water column than among animals living on or in the sea floor. No land animal larger than a cat survived.

• The largest air-breathing survivors, crocodilians and champsosaurs, were semi-aquatic. Modern crocodilians can live as scavengers and can survive for as long as a year without a meal. And modern crocodilians' young are small, grow slowly, and feed largely on invertebrates for their first few years - so they rely on a detritus-based food chain.

It is not clear how long the K-T extinction took. Some theories require a rapid extinction (few years to a few 103 years), others require longer periods. It has also been argued that some dinosaurs survived into the Paleocene. This favors a gradual extinction of the dinosaurs. But this seems now very unlikely because all the remains found are fragments which could have been reworked.

Pope, D'Hondt, and Marshall [191] claimed that mass extinction of marine plankton appeared abrupt and right at the K/T boundary. Marshall and Ward (1996) found a major extinction of ammonites at or near the K-T boundary, a smaller and slower extinction of ammonites associated with a marine regression shortly before that, gradual extinction of most inoceramid bivalves well before the K-T boundary, and a small, gradual reduction in ammonite diversity throughout the very late Cretaceous. This analysis may favor the idea that several processes contributed to the mass extinction in the late Cretaceous seas.

5.3.2.3 The Impact and its Consequences

The asteroid that has impacted near the coast must have caused gigantic tsunamis. Evidence for such a scenario has been found all round the coast of the Caribbean and eastern USA - marine sand in locations that were then inland, and on the other hand, vegetation debris and terrestrial rocks in marine sediments dated to the time of the impact.

The crater's shape suggests that the asteroid landed at an angle of 20° to 30° from horizontal travelling north-west. This would have directed most of the blast and solid debris into the central part of what is now the USA. Some of the most severe consequences were as follows:

• Global dust cloud: this blocked sunlight and photosynthesis became reduced for years. The extinction of plants and phytoplankton as well as of all organisms dependent on them was a consequence. This includes also the predatory dinosaurs and herbivores. However, it is clear that organisms whose food chain were based on detritus could have survived. Moreover, the asteroid landed in a bed of gypsum (calcium sulphate), which would have produced a vast sulphur dioxide aerosol. This would have further reduced the sunlight.


World's third largest asteroid impact zone found in South Australia

The asteroid hit Earth up to 360m years ago, the study found. Credit: NASA

An asteroid measuring up to 20km across hit South Australia up to 360 million years ago and left behind the one of the largest asteroid impact zones on Earth, according to new research published today.

The impact zone in the East Warburton Basin was buried under nearly four kilometres of earth, said Dr Andrew Glikson, a visiting fellow to the Australian National University's Planetary Science Institute and a co-author of the paper.

"It's significant because it's so large. It's the third largest impact terrain anywhere on Earth found to date," Dr Glikson said.

"It's likely to be part of a particular cluster that was linked with a mass extinction event at that time."

Dr Glikson published his findings in a paper in the journal Tectonophysics, co-authored by ANU colleagues Dr John Fitzgerald and Dr Erdinc Saygin and by the University of Queensland's Dr Tonguc Uysal.

The team analysed quartz grains drawn from over 200 samples taken from far below the Earth's surface and studied underground seismic anomalies.

Dr Glikson said there was a chance that the asteroid that caused the impact zone actually split in two before it hit.

"We are studying another anomaly in West Warburton that could well be its twin but we don't know yet."

Dr Simon O'Toole, Research Astronomer at the Australian Astronomical Observatory, said the finding was very interesting.

"It strengthens the case for the idea that the Chicxulub crater is connected to the mass extinction of the dinosaurs. We are starting to see more evidence that impact events caused mass extinction events," said Dr O'Toole, who was not involved in the research.

"Australia is a fantastic place for impact crater hunters because we have huge open space with nothing in it," said Dr O'Toole, adding that the size of the new impact zone was very significant.

"It's huge. Most asteroid events are about 100m in diameter."

Another asteroid, dubbed 2012 DA14, will pass within 27,700 kilometres from Earth on Saturday, potentially passing communication satellites, but is unlikely to hit the planet.

This story is published courtesy of The Conversation (under Creative Commons-Attribution/No derivatives).


What would a 220km diameter asteroid impact do to Earth? - Astronomy

If an asteroid / meteorite of about 10 km in diameter hit either a) land or b) ocean, on earth, what may happen?

For an asteroid 10 km in diameter, it doesn't matter where it hits, ocean or dry land. Remember that the depest point in the oceans is in the Mariana Trench, and is only 11 km deep! Also, a typical speed for meteorites is around 30 kilometers per second. An asteroid 10 kilometers across is so massive that it's very hard to slow it down. Unlike smaller meteors, it will not be slowed down much by air friction. It will punch through the atmosphere like it's hardly even there. When it reaches the surface, it will smack so hard that it won't matter if it strikes ocean or land.

The imapact with the earth's crust will finally stop the asteroid. The energy of the impact will vaporize the asteroid and a large amount of the Earth's crust, creating a crater more than one hundred kilometers across, throwing all that rock into the air.

Some of this debris will be going so fast that it will fly right out of the Earth's atmosphere and go into orbit around the Earth. Most of the debris will rain back down on the Earth--every part of the Earth, not just near the impact site--heating the atmopshere until it's like the inside of an oven, triggering forest fires and cooking anything that isn't sheltered underground.

The combination of dust from the impact and soot from the forest fires will remain in the Earth's atmosphere for a year or so, blocking the light of the Sun. Without sunlight, much of the Earth's plantlife, on land and in the sea, will die.

Many species of animals--including the human race, if we aren't both lucky and resourceful!--will die out, either in the initial catastrophe, or in the ensuing years due to lack of food and the general devastation of the environment.

The last time this happened was 65 million years ago, when an asteroid struck the Earth, creating the Chicxulub Crater in Mexico and causing the extinction of the dinosaurs. On average, an asteroid this size strikes the Earth every 50 to 100 million years.

This page checked on July 18, 2015.

About the Author

Britt Scharringhausen

Britt studies the rings of Saturn. She got her PhD from Cornell in 2006 and is now a Professor at Beloit College in Wisconson.


Why Is the Chance of an Asteroid Impact in 2032 Going Up? [Don’t Panic!]

I recently wrote about a newly discovered asteroid called 2013 TV135. This 400-meter-wide rock has an orbit that takes it out from the Sun past Mars and dips it inward to just inside Earth’s orbit. The orbit is tilted with respect to Earth, but it does sometimes get fairly close to Earth.

When it was discovered on Oct. 8, astronomers projected its path forward in time to see just how close it might get. They found that in August of 2032 it may give us a close shave indeed: Given what they knew at the time, they calculated that there was a 1 in 63,000 chance of an impact.

As I wrote before, that number needs to be taken with a 400-meter-wide grain of salt. It’s essentially impossible to predict where an asteroid will be 19 years from now based on a week’s worth of observations. Over time, as we get more information on it, we’ll be able to nail down its orbit. Chances are an impact will be ruled out.

However, a few days ago a BABloggee sent me an email alerting me that the JPL Near Earth Object Risk Assessment website had listed the odds of an impact at 1 in 14,000. That means an impact is more likely! Should we panic?

My advice is to heed Douglas Adams’s advice: Don’t panic. Counterintuitively, having the chance of an impact go up at first is natural as more observations come in, but it’s still far more likely that the chance of an impact will drop to zero as time goes on. Even though at first this seems weird, the reason behind this is actually pretty simple.

Because we don’t know the exact position, speed, and direction of an asteroid at first, projecting the orbit into the future makes it fuzzy. If you pick some time, say 19 years from now, there is a most likely position you can calculate for the rock, but really, statistically speaking, it could be anywhere inside a largish volume of space.

If the Earth is also inside that volume of space at the same time, then there is a chance of impact. But the volume is large, and the Earth small. That’s why, at first, the chance of an impact is usually pretty small.

So why does the chance then go up with more observations?

One way to think of this is to reduce it to a two-dimensional problem, which is easier to imagine. It’s not wholly accurate, but it’s just to give you an idea of how this works.

Picture a big circle hanging in space. At some future time, all we can say is that the asteroid will pass somewhere through that circle it might be dead-center, or it might be near the edge. Now let’s say the Earth is also inside that circle but off-center:

Since the asteroid could pass through this circle anywhere inside it, the chance of it hitting the Earth is really just the ratio of the area of the Earth to that of the big circle. In the case here, I drew the circle with 50 times the diameter of the Earth. The ratio of the areas is 2,500 to 1 (area scales as diameter squared), so the chance of an impact is only 1/2,500 or 0.04 percent. Pretty low!

Illustration by Phil Plait

Now let’s say that more observations have nailed down the orbit a little better. The circle representing its probable location gets smaller. Let’s say it shrinks to 40 times the Earth’s diameter:

Note that the Earth is still inside the smaller circle. So now the odds of an impact are 1 in 1,600, or 0.06 percent. That’s higher! That means an impact is more likely. Or is it?

Illustration by Phil Plait

Now let’s say we get even better observations, and the circle gets even smaller, this time 25 times the Earth’s size:

Illustration by Phil Plait

Hey, wait a sec. The Earth is now outside the circle! That means the odds of an impact drop a lot. You might think the chance becomes zero, but really I’m hugely simplifying a much more complex issue this is an analogy. In reality the chance won’t go completely to zero once the Earth is outside the target region because that circle isn’t really a hard-edged reality in space it’s more of a big fuzzy region. Still, unless the Earth is placed just so, as time goes on the mathematical chance of an impact drops ( … I almost wrote, “like a rock”, so, um, yeah).

This is what happened with the asteroid 99942 Apophis back in 2004. At first, estimates for an impact were about 1 in 200, and that chance quickly rose to a gulp-inducing 1 in 37 (a 2.7 percent chance of impact). That’s still low, but given the consequences, a bit too high for my taste. However, as the orbit was refined further, the chance dropped, and then in early 2013 an impact was finally ruled out.

This is likely to be the case for TV135 as well. The first estimates of an impact chance were made with only eight days of observations we now have 13 days, which is marginally (though not much) better. I fully expect we’ll see the chance of an impact go up even more for a while — as of Oct. 23 the chance had risen marginally to 1 in 10,000, which is still pretty small — but given some time I also expect the chance will probably drop once again.

To be honest, of course, I can’t guarantee that, but it’s the way I’d bet (cripes, most people would scoff and walk past any table in a casino that gave 10,000-to-1 odds of a win). And not to be too ominous, but even if this rock winds up missing us, there are a lot more out there. We’ve only mapped 10,000 out of a million or so dangerously large near-Earth objects, or about one percent of them. As I’ve said many times, we need more eyes on the sky, and a plan in place if we ever do spot one where the chance of an impact increases over time… and doesn’t change its direction.

Tip o’ the Whipple Shield to asteroid expert Don Yeomans for help with this topic.


The false news

There are several versions of this false news circulating on the internet with some small differences between them, which adds that “cordless phone” effect, where with each version, the message seems to depart further from reality.

The basis of all these materials is the asteroid 2009 JF1, which was discovered in 2009 and would be being monitored by NASA due to its risk of impact in 2022. The asteroid would have about 130 meters in diameter and energy equivalent to 230 thousand tons of dynamite , which would be about 15 times more powerful than the atomic bomb that exploded over Hiroshima at the end of World War II.

According to the publications, the Asteroid will approach Earth on May 6, 2022, with a chance of impact of 1 in 3800, that is, a 0,026% chance of reaching our planet that day.

Article in regional news portal

The probabilities of impact appear to be increased in the headlines of some variations of this news. In some, the impact "can occur", in others, "must occur" and there are even those who crave a "will occur", typical of the most hyped apocalyptic sources. 'Less badly' that, even in the most alarming versions, the space agencies Nasa and ESA are the ones that inform ou warn for impact, rather than being the ones hide the possibility, as we normally see in conspiracy publications.

But in fact, neither NASA nor ESA warned of the 2009 JF1, simply because this asteroid poses no risk and there is not enough information to know even when it will approach Earth.


NASA Says 500-Foot Wide Asteroid Approaching Earth Is 'Potentially Hazardous'

An asteroid estimated at between 70 and 160 meters (230 to 525 feet) in diameter will make a "close approach" to Earth next week, according to NASA. The rocky object, referred to as 2016 NF23, is traveling at around 20,000 miles per hour&mdashfaster than many rockets.

Data from the space agency's Earth Close Approaches website indicates that the Near Earth Object (NEO) will come nearest to our planet on August 29.

NEOs are any asteroid or comet whose orbits bring it into the inner solar system within about 121 million miles of the sun, and also within about 30 million miles of Earth's orbit.

If the orbit of an NEO at the time of its discovery is such that there is a (typically small) chance it will collide with Earth and cause significant damage, it is labeled "potentially hazardous," according to the Swinburne Astronomy Online Encyclopedia.

The asteroid, or other object, must have a minimum approach distance of less than 0.05 astronomical units or roughly 4.6 million miles to be classified as such. At its closest approach, 2016 NF23, for example, will be approximately 3.1 million miles (or 0.033 astronomical units) away from Earth. Fortunately, this means there is no danger of a strike.

If an asteroid the size of 2016 NF23 did crash into our planet it would cause significant damage on the scale of entire countries. A strike involving a larger asteroid greater than a kilometer (0.62 miles) in diameter would have global consequences if it crashed into Earth.

Aside from the massive destruction resulting from the initial impact, the global climate would be affected, leading to widespread crop failures and loss of life, among other effects.

Once potentially hazardous asteroids or other objects, such as comets, are discovered, they are monitored continually by observatories around the world. Over time, their orbits may be disrupted through gravitational interactions with other planets or bodies, increasing or decreasing the risk of a collision, according to the Swinburne Astronomy Online Encyclopedia.

But even though the orbits of "potentially hazardous asteroids" are uncertain,"it is possible to estimate the size of these uncertainties and place corresponding limits on close-approach distance and time," according to NASA.


Watch the video: Διέλευση αστεροειδή κοντά στη Γη. 24092020. ΕΡΤ (June 2022).


Comments:

  1. Northrop

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  2. Flynt

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  3. Paul

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  4. Macen

    It is the lie.

  5. Ranier

    Also what as a result?



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