Why Hasn't An ELE-object Hit Earth Yet And Wiped Us All Out?

originally posted by: StallionDuck
Much of what others mentioned plus.....

Space is really really big!

Imagine scooping up a handful of pebbles and throwing them one by one at a basketball that's some hundred yards away.

Now think about chunking a mile wide asteroid at a little blue planet some gazillion bizzilion miles away.

It is just not time yet!

Have you ever looked at the masses that cross our path regularly?
We have our wonderful stargazing times each month as we pass through other masses of them called Meteor showers.
Some of these have large ones in the population.

Roughly 1000 near-Earth asteroids are known, ranging in size up to approximately 32 kilometres (1036 Ganymed). Tens of thousands probably exist, with estimates placing the number of NEAs larger than one kilometer in diameter at up to 2,000. NEAs only survive in their orbits for 10 million to 100 million years.

They are eventually eliminated by orbital decay and accretion by the Sun, collisions with the inner planets, or by being ejected from the solar system by near misses with the planets.

Such processes should have eliminated them all long ago, so it is assumed they are resupplied on a regular basis by orbital migration of objects from the asteroid belt.

A leading astrophysicist from Queen's University Belfast has warned that an asteroid strike is just a matter of time.
www.sciencedaily.com...

Asteroid about 100 metres in diameter - Traveling 24 kilometres a second has just missed the Earth
www.abovetopsecret.com...

a reply to: SeaWorthy

And yet, space is mostly empty. All the mass in the universe only occupies 0.0000000000000000000042% of space.

The solar systems been around for a very long time and, due to this, the majority of stuff that has been flying around with an impact trajectory has already hit the Earth. Although, other space rocks and such sometimes get pulled in due to gravity, which may cause some issues in the future, i.e. death and destruction.

a reply to: AnakinWayneII

Extraterrestrials are protecting their experiments.

originally posted by: AnakinWayneII
It's a simple question.

Why hasn't a killer asteroid or something smashed into Earth and wiped us all out?

Did Harry Potter wave his wand or something and say "Avada Kedavra".

It's a simple question. With the amount of rogue bodies whizzing through space in and around our solar system, why haven't we been smashed into smithereens yet?

We have been smashed to smithereens—many times—but you don’t remember it because it happened more than 4 billion years ago. By about 4.5 billion years ago, the Solar Nebula had cooled to the point where metals and silicates solidified and stuck to each other enough to form primitive planetisemals (a few km in diameter). The evidence for this is the fact that almost all meteorites that have been collected on the Earth have been radiodated to an age of 4.5 billion years, plus or minus a little bit. So, we know that metallic and stony bodies were floating around in the Solar System by that time.

Once there are solid bodies being formed, each one becomes a center of gravitational attraction for others, and they quickly grow in size by gravitationally capturing each other. This has the effect of sweeping up all the large number of small bodies into a small number of very large bodies which roughly correspond to the planets we know of today. (Celestial bodies at this stage of development are usually referred to as protoplanets).

Models show that the period of time elapsed from the point where metals and silicate grains precipitated out of the Solar nebula until protoplanets such as Earth, Mars, Mercury, etc. had formed was very short by cosmic time—about 1 million years.

After protoplanets were formed, there were still a lot of remaining planetisemals left over and they began to be captured by the protoplanets. The term “captured” sounds pretty benign, but when a protoplanet the size of Earth “captures” a planetesimal 100 km in diameter travelling at 20 km/sec, the collision releases all of that kinetic energy instantly, which forms craters, creates fissures in the protoplanet and releases heat which causes lava flows that resurface the protoplanet. The period from about 4.5 to 4.0 billion years ago during which this process occurred is referred to the period of Heavy Bombardment. On Earth, evidence of these impacts has been mostly erased through the action of weathering, tectonics, and the formation of oceans. However, the Moon has none of those processes, so its history of impacts is easy to read by determining the sizes and ages of craters. When that kind of crater counting is done, it shows that the Heavy Bombarbment ended about 4.0 billion years ago.

The oldest fossilized life forms discovered so far (cyanobacteria stromatolites) go back to about 3.5 billion years ago, implying that more primitive forms of life appeared before that--maybe only a couple of hundred million years after the end of the Heavy Bombardment. Since it didn’t take very long for life to appear once the surface environment became stable, it’s possible that life could have started on Earth more than once during the Heavy Bombardment and then been extinguished by subsequent impacts.

In any case, the period of Heavy Bombardment used up most of the planetesimals of the Solar System, leaving only the Asteroid Belt as the last source of planet impactors (except for the comets, but that’s a different story). Orbits in the Asteroid Belt between Mars and Jupiter are relatively stable, but the combined gravitational pulls of Mars and Jupiter can act together in such a way as to occasionally pull asteroids out of the main belt and send them on a slow journey into the inner Solar System. Inevitably, some of them can end up crossing Earth’s orbit where they become potentially hazardous impactors.

Starting 20 or 30 years ago, NASA and other agencies started identifying and tracking as many asteroids 1 km diameter and larger that could cross Earth’s orbit as possible. Asteroids that size are relatively easy to spot with Earth based telescopes, and NASA has identified about 90 percent of the potentially hazardous population in that size range without finding any that are on a collision course. There are a number that are in the 100 meter diameter range that can potentially get close enough to collide with Earth, and NASA forecasts their trajectories out 100 years or so into the future so that there would be plenty of warning time to do something about it.

At this point in the evolution of the Solar System, there is very, very little chance of a 100 km diameter asteroid (like the one that killed the dinosaurs) sneaking up on us without warning.

originally posted by: AnakinWayneII
It's a simple question.

Why hasn't a killer asteroid or something smashed into Earth and wiped us all out?

Cosmic black operations and technology.

a reply to: AnakinWayneII

Why hasn't a killer asteroid or something smashed into Earth and wiped us all out?

Give it time, it will, unless we kill ourselves off first.

Considering the relatively short time humans have been on this planet in the grand timeline of universal events.

Because you won't stop touching yourself.

I'll just say luckily odds are in our favor. If they were not we wouldn't be here. But like in all things luck can run out hopefully by then we will be abled to avert the disaster.

In truth doesnt take alot to change a path if it's far enough away. Could be as simple as slamming a spacecraft into it.

Why Hasn't An ELE-object Hit Earth Yet And Wiped Us All Out?

One easy answer
The Laws of Probability
They rock..

a reply to: 1947boomer

There are a number that are in the 100 meter diameter range that can potentially get close enough to collide with Earth, and NASA forecasts their trajectories out 100 years or so into the future so that there would be plenty of warning time to do something about it.

Yeah until this happens every year or so
Asteroid about 100 metres in diameter - Traveling 24 kilometres a second has just missed the Earth

www.abovetopsecret.com...

originally posted by: AnakinWayneII
It's a simple question.

Why hasn't a killer asteroid or something smashed into Earth and wiped us all out?

Give it time. Humans have been around for only a "blink of an eye" in the history of the Earth. Heck, even the 65 million years since the last ELE asteroind impact that wiped out the dinosaurs is only a short amount of time in the long life of the Earth.

Put it this way, if the entire 4.5 Billion year history of Earth were condensed into a 24-hour day, humans did not arise until the last two minutes of the day (at 11:58:45 PM). The extinction of dinosaurs would have also happened very late in the day -- sometime around 11:40:00 PM.

So in the grand scheme of things, even the asteroid that is thought to have wiped out the dinosaurs (or at least contributed to it) was a very recent event in the history of Earth.

So give it time. It might happen next week, or next century, or in 50,000 years, or longer. "50,000 years from now" is not much different than "now" when the entirety of Earth's history is considered.

The randomness of the universe is why. Maybe it will happen today or tomorrow or maybe it never will. Maybe we will just fizzle out as a result of a bunch of unfavorable circumstances conspiring to extinct us.

Anyway, we exist for the same reason that we haven't ceased to exist. There isn't a reason. Just random chance.

originally posted by: Vector99
a reply to: AnakinWayneII

You can thank Jupiter for that

I've never quite understood that reasoning. Jupiter is big, but compared to space it's a speck of dust, and it's not even aligned with us and the sun most of the time. Unless a big rock actually hits it, it's just as likely to slingshot a comet right at us as it is to protect us.

a reply to: AnakinWayneII

Oh, don’t forget about a gamma ray burst.

Star spotted on the brink of a gamma ray burst – and it's alarmingly close to Earth

newatlas.com...

a reply to: neutronflux

Would not even know it till it hit you.

originally posted by: Blue Shift

originally posted by: Vector99
a reply to: AnakinWayneII

You can thank Jupiter for that

I've never quite understood that reasoning. Jupiter is big, but compared to space it's a speck of dust, and it's not even aligned with us and the sun most of the time. Unless a big rock actually hits it, it's just as likely to slingshot a comet right at us as it is to protect us.

It is not the size, but the mass/gravity of Jupiter that matters. The idea is not that it shields earth directly, but that it reduces the number of objects entering the inner solar system by slingshooting them away.

But yes, there is at least one known case where Jupiter deflected a comet towards earth first and threw it out of the solar system when it came close to Jupiter again.

Jupiter is also the reason for the asteroid belt, does not allow the asteroids to bunch together, create a planet.

The argument is that the positive effect outweighs the negative. I would like to see some numbers/simulations showing that though.

a reply to: 1947boomer

Yeah, what he/she said

a reply to: AnakinWayneII

Well, on average, which isn't very scientific, big ones hit about once in 10,000 years. Be patient.

a reply to: AnakinWayneII

Earth or the Sun/Jupiter are tiny objects compared to the vast volume of empty space that exists in our physical universe...

next off, the fabric of time-space that's laced with Gravity will always tend to eliminate head-on collisions resulting in complete disintegration of opposing objects larger than proto-planets/ dwarf planets in mass