U.S. CitiesCity-Data Forum Index
Go Back   City-Data Forum > General Forums > Science and Technology > Space
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
Reply Start New Thread
 
Old 05-24-2019, 02:51 PM
 
22,774 posts, read 17,250,171 times
Reputation: 9481

Advertisements

Quote:
Originally Posted by Neuling View Post
They mention the size of 1 km, that is huge. It would take quite some power to change the path of or destroy such a massive object, especially given the speed of those objects. The speed and mass of such an object add up, so to speak.
The angle of deflection of the asteroid would only have to be very small if the impactor hit the asteroid while it was far enough away from earth. This method would only work on asteroids that were years away from hitting the earth.

But I just now came upon this article in which a new study indicates that this wouldn't work with an asteroid like Bennu and that as many as 50 different rocket launches would be necessary and still might not work.
https://www.independent.co.uk/news/s...-a8259806.html


Quote:
In this context: when there is no air in space, is it even possible to create, say, an explosion next to an asteroid in order to change its course? When there is no air, there is no change in air pressure so to speak that could push the object away, right?
Space isn't a perfect vacuum. It contains gas, plasma and dust which would provide a medium for a shock wave. I don't know how powerful a shockwave in space would be.

A gravity tractor might work. A probe would ride along side an asteroid and its slight gravitational pull would over a long period of time affect the path of an asteroid. Again though, this wouldn't work on an asteroid that was only months away from impacting earth.

Perhaps the best shot at ending the threat, especially if the asteroid was a near term threat would be to explode a powerful nuclear bomb or bombs on the surface and hope for the best. But this might result in many smaller fragments hitting the earth's surface instead of one big piece.


Quote:
And on a more general level, how does propulsion in a vacuum work?!
Newton's third law: For every action, there is an equal and opposite reaction. Any action produces an equal and opposite reaction, whether in a vacuum or not. Produce thrust out of one end of a space craft and it propels the craft in the other direction.

Or, using a solar sail, the pressure exerted by photons from the sun on the sail would produce thrust for a spacecraft. It would ride the solar wind.
Reply With Quote Quick reply to this message

 
Old 05-24-2019, 03:15 PM
 
Location: West Coast of Europe
22,364 posts, read 19,821,845 times
Reputation: 8820
The danger of shooting at it might be that the result is largely unpredictable, not least since the object is probably not symmetrical and homogeneous. It might even make the object more likely to hit our planet if it breaks apart the wrong way.

One might think of a way to use the incredible kinetic energy of the object and turn it against itself somehow.
Reply With Quote Quick reply to this message
 
Old 05-30-2019, 07:53 PM
 
6,990 posts, read 6,737,803 times
Reputation: 5188
Quote:
Originally Posted by RocketDawg View Post
And you base you opinion on what?
They are professional liars and con artists for starters and people have proven it.
Reply With Quote Quick reply to this message
 
Old 06-04-2019, 02:36 PM
 
2,710 posts, read 3,001,905 times
Reputation: 1227
Quote:
Originally Posted by CookieSkoon View Post
I will be in my mid forties by then. I pray it hits us.

I will be dust by then. Well, the body will. Without taking it along, maybe I can hitch a ride to Pern.
Reply With Quote Quick reply to this message
 
Old 06-07-2019, 07:31 AM
 
Location: Holly Springs, NC
1,414 posts, read 806,923 times
Reputation: 2177
Quote:
Originally Posted by elnina View Post
There is probability of up to 2.7% that it would hit Earth on April 13, 2029.
The morning drive radio show was talking about this on my way into work this morning. My question is, how can scientists predict, with certainty, the date an object will pass near earth but not know with certainty it will hit earth? It seems to me, the average person, if you know one you should know the other.

What are the variables that would make that a 100% event or a 0% event?
Reply With Quote Quick reply to this message
 
Old 06-07-2019, 09:32 AM
 
Location: Somewhere in northern Alabama
18,514 posts, read 55,435,808 times
Reputation: 32216
" My question is, how can scientists predict, with certainty, the date an object will pass near earth but not know with certainty it will hit earth? It seems to me, the average person, if you know one you should know the other."

When I pee off my back deck, I know with 100% certainty the second it will hit the ground, but not which blade of grass or squirrel it will hit. When I sight in my rifle, I know when the bullet will hit the target, but not which precise spot. When the path of an asteroid is computed, the exact direction has a margin of error, even as the speed can be precise enough to predict a date of arrival. When a sperm... ... nevermind.
Reply With Quote Quick reply to this message
 
Old 06-07-2019, 10:42 AM
 
Location: West Coast of Europe
22,364 posts, read 19,821,845 times
Reputation: 8820
Yes, you have to consider how tiny Earth is in the middle of the vast universe. Like the needle in the haystack. It is already an achievement that we can predict that something is coming in our direction.
The closer it gets, the more precisely we can predict whether or not it will hit us, and ultimately where on Earth it would hit.
Reply With Quote Quick reply to this message
 
Old 06-08-2019, 09:16 PM
 
832 posts, read 809,183 times
Reputation: 505
Quote:
Originally Posted by harry chickpea View Post
" My question is, how can scientists predict, with certainty, the date an object will pass near earth but not know with certainty it will hit earth? It seems to me, the average person, if you know one you should know the other."

When I pee off my back deck, I know with 100% certainty the second it will hit the ground, but not which blade of grass or squirrel it will hit. When I sight in my rifle, I know when the bullet will hit the target, but not which precise spot. When the path of an asteroid is computed, the exact direction has a margin of error, even as the speed can be precise enough to predict a date of arrival. When a sperm... ... nevermind.
One is that the masses of the object and its path is not path are not precisely known. Another is the position of three or more planetary objects is impossible to calculate precisely. The best we can do are approximate calculations. See three body problem.

The uncertainty in the path can be visualized as a circle with the object at its center. Initially they say that the predicted path will fall within a large circle which include the earth. The closer it gets the smaller the circle gets. When the circle gets smaller than the earth and is entirely within the earth it can be said with certainty that it will hit the earth. As the circle decreases in size we can more precisely predict where the object will hit. That might not be known until a matter of hours before impact.
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply
Please update this thread with any new information or opinions. This open thread is still read by thousands of people, so we encourage all additional points of view.

Quick Reply
Message:

Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Science and Technology > Space
Similar Threads
Follow City-Data.com founder on our Forum or

All times are GMT -6. The time now is 10:10 AM.

© 2005-2019, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 - Top