An asteroid will hit Earth at some point. What can we do about it?

A big powerful laser beem.
It will cause ablation of material where the asteroid is hit and will tend to push it away from that direction.
It will require a huge solar array in cislunar space or on the moon and during its 'down' time it can beam green energy down to us on Earth.

Easy peezy.

(I've seen how they do it in the movies.)
 
The temptation to overcome distance is an illusion.
I have children, grandchildren, and great grandchildren. They inform me (a lifelong student of history among other things) in too many ways for you to understand that the future of birthing new and expanding frontiers is no different than the past of birthing new and expanding frontiers. History always repeats in large even if not in small details (noted historian Will Durant, among others).
 
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In a scale model, if the Sun was a golf ball, the Earth would be a mustard seed about 20 feet away. The nearest star another golf ball 736 miles away. It would take us about a year, with current technology, to reach the Sun. Figure 200,000 years to the nearest star, plus rest stops.
 
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There is earth dreaming and space dreaming. The difference is so great they can not compare. Space travel will remain fiction. If one thinks solar travel is space travel, ones needs to rethink space.

It ain't gonna happen. But of course that statement is a challenge for many.

But it's truly not a dare, it's simply a hard fact.

For your great, great, great grandchildren.
 
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There is earth dreaming and space dreaming. The difference is so great they can not compare. Space travel will remain fiction. If one thinks solar travel is space travel, ones needs to rethink space.

It ain't gonna happen. But of course that statement is a challenge for many.

But it's truly not a dare, it's simply a hard fact.

For your great, great, great grandchildren.
You would fit in perfectly with the naysayers of all ages.
 
In a scale model, if the Sun was a golf ball, the Earth would be a mustard seed about 20 feet away. The nearest star another golf ball 500 miles away. It would take us about a year, with current technology, to reach the Sun. Figure 100,000 years to the nearest star..
It's a good thing you said, "current technology", Bill. A couple of hundred years ago, even less, people couldn't fly the skies, much less orbit the Earth, with their brand of "current technology."
 
Ad #11:

There were physics existing that the people of those times were unaware of. There are physics in and to the universe existing that we are unaware of today, regardless of those people who think we in our isolation know everything there is to know regarding physics and the universe at large . . . today!
 
We have known for many decades of this real danger. And we get a little lip service about it. There are many optical, IR and radars scanning the vicinity. But in my opinion this a just a cover approach.

It will take a large hit or a very close scare before any real concern is taken. And that's doubtful. They would say the chances of getting hit again are astronomical.

Just watch.
 

Wolfshadw

Moderator
Ad #11:

There were physics existing that the people of those times were unaware of. There are physics in and to the universe existing that we are unaware of today, regardless of those people who think we in our isolation know everything there is to know regarding physics and the universe at large . . . today!
Have to agree with @Atlan0001 on this one. We've barely scratched the surface of understanding the physics of the Universe. If we can somehow manage to survive the next few millennia without getting wiped out (or destroying ourselves), then I think that's one nut we might actually crack.

-Wolf sends

Oh... and let's keep the disparaging remarks out from here on out.

Wolfshadw
Moderator
 

Catastrophe

"Science begets knowledge, opinion ignorance.
Has anyone considered the following?

What is the speed of an asteroid approaching Earth?

Asteroids, the most common type of impactor, slam into the Earth at an average velocity of 18 km/s. Short-period comet impacts with the Earth are less common, but have higher impact velocities averaging 30 km/s.

Now consider how far an asteroid may travel after it has been seen, recognised as a potential threat, and preparations completed to launch, and despatch?

How fast will our countermeasure travel? How long will it take to slow it down, if, as in some scenarios, its speed must to reduced to match that of the asteroid? Vide gravitational effects?

How far away (or how close) will any potentially hazardous asteroid (or other body) be before it is discovered? Remember comets only develop visible tails on approaching the inner solar system.

They seldom pass close enough to Earth that they become bright enough to observe, and so most can only be observed when within a few million kilometers of Earth. They therefore cannot usually be catalogued well in advance and can only be warned about, a few weeks to days in advance. (Google)

Of course, impacts with very large bodies are unlikely. But . . . . . .

Chodas-Day2-Briefing (nasa.gov) Note: this is an exercise only.

The new measurements did not eliminate the possibility of impact, as had been hoped; IAWN now estimates the impact probability at 96%

Asteroid 2017 PDC is on a course that almost certainly will impact the Earth on July 21, 2027



Cat :)
 
It's a good thing you said, "current technology", Bill. A couple of hundred years ago, even less, people couldn't fly the skies, much less orbit the Earth, with their brand of "current technology."
I take current technology to include fisson and fusion. None of them is sufficient for interstellar travel in a human lifetime. Only antimatter could do, and it is not possible to make or store enough. Maybe some time in the future they will invent cheap, readily available antimatter.
 
I take current technology to include fisson and fusion. None of them is sufficient for interstellar travel in a human lifetime. Only antimatter could do, and it is not possible to make or store enough. Maybe some time in the future they will invent cheap, readily available antimatter.
Per your view above, you establish space as rigidly absolute. I don't. The instant a constant acceleration drive ship -- a gravity drive ship -- leaves the vicinity of Sol for another star, it begins shrinking, contracting, the local relative universe before it , , , effectively counteracting the seeming accelerating expansion of the universe, which according to you, fixing outer space to the turning wheel on the ground surface of the Earth, it cannot do.

Think, Bill! See yourself midpoint between many distant star-POINTS in interstellar space. Points "at a distance" (Einstein), Bill. None of those stars, none of those POINTS, are like ground markers on the surface of the Earth. It's more like having descended down and in into the microcosm as well as having ascended up and out into the macrocosm (effectively, you've done both). You are under constant acceleration, thus time itself, light time itself, SPACETIME itself, to your fore is under constant acceleration, accelerating histories forward in time from behind in time, faster and ever faster, minute by minute passing on your ship's clock which will be minute by minute accelerating to your minute passing, hour by hour accelerating to your minute passing, day by day to your minute passing, week by week to your minute passing..., of observable history to your fore, the universe of space observably literally accelerating in contracting in space ahead before you, while equally but oppositely -- anti-gravitationally -- accelerating expanding in space and dropping away into the past behind you so to have traded places in light years (observed years per light at the speed of light, though not real years) with your stellar destination, the real destination you cannot possibly observe until you rendezvous with it's object reality -- where and when you get to the merger point of observed SPACETIME universe and previously unobservable spontaneous concurrent REALTIME universe.

If all you could do was trade minute for minute when you go in motion, without any acceleration of motion or time, you'd never get across the street, or out of any kind of space you occupy, much less across interstellar distances. Also, Bill, there is no way for travelers under self-powering constant acceleration to measure speed between those distant stars, between those distant points of light, or while crossing, surfing, crisscrossing waves of intersecting push-pull gravity/antigravity interfaces. It's a multi-body space and time placement / triangulation problem like the three body problem that wrecks your inertially inert [observed space of the universe] geometry.

The speed of the UFOs getting here and leaving, if existent, is something to wonder about. The possible speed of asteroids coming through interstellar distances without many and distant hunter-gatherer eyes looking out for them, is something far worse for not being alien ships (ships as such).
 
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Ad #19:
It, such travel ascending into the macrocosmic realm, would be exactly as if the self-powering traveler had descended into the microcosmic quantum realm. More, actually, the self-powering traveler would descend into the microcosmic quantum realm until it gained effective relativity to its REALTIME destination. Try that on for size!
 
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I think Meteorite Defense is the best goal of all for long range, ambitious space programs. I wish I could find the US survey that showed that was the single most supported goal for NASA.

One modest sized impactor any time soon would bring home the value of such a scheme. Instead of saving of some small portion of humanity by establishing human colonies in space - which is a money sucking fantasy that is not anywhere close to being viable - it is defending the lives and homes and futures of the greatest numbers. Including the people and economies that fund and provide technology and services to space agencies, who, not surprisingly, have no actual plans for any permanent habitations in space.

Immediate results? No. It will need to be a long range goal to have early enough warning and a capability to meet and divert a real threat.

If that program creates opportunities for businesses and people in space I don't doubt it will be taken advantage of. But I think colonies will only happen as an emergent outcome from doing things in space of direct value to the nations and people on Earth.
 
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The primary constrain with deflecting meteoroids seems to be time. If NASA had a 10-year warning, then there's no doubt in my mind that we would find a solution with current technology. IDK if it's sufficient, but We already have a system to track meteoroids. So what should our Earth Meteoroid Deflection System be? I'll be calling it the "E.M.D.S." for brevity, but please tell me if there's already a term for this.

NASA's already tested meteoroid redirection with DART. So I think it makes the most sense to assume we'll use a DART-like system. Does anyone know what the mass of the system should be?

I think the E.M.D.S. should be a fleet of spacecraft instead of one large one because if there's a small meteoroid, then we only send some of them and we get multiple shots. But it would need political shielding because it looks a lot like an ASAT system.

Making it an international program should do the trick. If you need permission from NASA and Roscosmos, then how could it even be used as a weapon? And hopefully we'd split the cost. We could even have dissimilar redundancy by having each space agency build a redundant system.

Where should they idle? Keeping them in space would make a response quicker, but it would also increase the burden of operations. If an E.M.D.S. spacecraft has issues in space, then fixing it will be much harder, take longer, and require more compromises. And if we can't fix it, then we have to deorbit it and launch a new one. But if we go with a fleet, then at least Earth would still be protected during this time.

If we keep the spacecraft on the ground, then it would take longer to respond, but issues are easy to deal with. Just make a few extra spacecraft and swap out the broken one. It might limit the amount of spacecrafts in the fleet, though.

It should be noted that the U.S.S.F. has an initiative called "Tactically Responsive Space"(TacRS), and it had a demonstration mission called "VICTUS NOX". They launched a spacecraft with only 24-hour notice. Firefly also wants to incorporate what they've learned from VICTUS NOX into normal operations for their current, and future, launch vehicles. But, IIRC, they won't have a fleet of launch vehicles ready at all times. They'll have only one launch vehicle prepared.

He added the companies would incorporate a similar level of responsiveness to MLV operations that Firefly is doing with Alpha. “It may not be 24 hours per se, but we’re going to bring the same responsive timeline mentality to the launch operations.”
- SpaceNews

Does anyone know how powerful and accurate a laser-based system, like @Questioner suggested, would need to be? Have we achieved anything like it before? If we have, then it would be a reusable solution, and it could be repurposed. @Questioner mentions beaming energy down to Earth, but if you don't believe in space-based solar, then it could be used to propel solar sails.
 
Just what many Europeans called the Americas circa 1490s-1510s, the "Louisiana Purchase," "Seward's Alaska Folly," and so on throughout history both before and ever since, "a money sucking fantasy"! Throughout history, people haven't changed, not one bit! You have the imperative [the future is now] frontier expansionist-energy minded and then you have . . . the other kind (oh, it's important but Earth first, last, in between and always, never ending (and always failing))!

They can't even see life's real relationship -- particularly mankind's real relationship -- to the Earth, much less to the world, the universe, outside the womb-world in a "due time of birth"!

Whatever their goals, including Earth defenses against extraterrestrial dangers, they won't attain them in a coming decline and decay of a world closed systematically isolated from frontier; Isolated from the expanding energies of an opening system which would as always be bound to frontier colonization (permanent occupancy). They won't have their world if they win their way! They will have what they made, if even that, and they won't like it one little bit! With their kind of minds they would deny even to themselves that they made it . . . as they are denying it today!

So, as always with frontiers in history, to borrow from Winston Churchill: Never in the field of human endeavor will so much be owed by so many to so few, the openers who find a way no matter the seeming invincible barriers (of not now!) always in place and always being raised. Given enough time, soon enough, they will one day see and capture the asteroid no one else saw in the first place to stop . . . or could stop.
 
The questions about feasibility depend on how big it is, how far we have to move it and how long we have. Just to pick some reasonable numbers:
- 100 meter diameter, density of rock, 4.5
- Ten years to move it
- Must move one Earth radius to get it out of the way

Volume = 523,000 m^3
Mass = 2,360,000 tons
Distance = 5,500,000 m
Time = 3e8 s

Distance = 1/2 a t^2
5,500,000 = 1/2 a (9e16)
a = 1.2e-10 m s^-2
F = ma
F= (2.36e9 kg ) (1.2e^-10)
F = 0.28 Newtons or about 28 grams, or one ounce, delivered for ten years.

If done in one, ten minute burst, a 600 pound force would suffice.
 
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The DART experiment knocked a lot of debris off of the asteroid. If used near the Earth, it could deflect the asteroid, but not the debris of boulders. Also consider what happens if the first shot misses, or doesn't deflect the asteroid enough ‒ will we need launch several impactors for a single asteroid?

A powerful laser might be more effective at deflecting the entire mass, especially if the laser can be pulsed in time with the asteroid's rotation. Possibly pulsing a giant laser will be cheaper and easier than launching a series of masses. And it certainly could be used to propel solar sails.

Hmm... Maybe SETI should be looking for laser light.
 
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