Science is good. Science is costly. NASA is finally doing a project that could benefit  inner-space ... but like Star Wars, we won't know if it works until we need it.

Good point Carl

Actually, I wonder if we could test it on an asteroid that will miss earth by millions of miles.............to see if we can alter its path.

Though there doesn't appear to be any big ones headed towards us currently, the biggest risk to humans, is by far from a large asteroid strike. 

It seems extraordinarily unlikely that there would be any changes in the suns very reliable output for the next million years. 

There will eventually  be another Tambora type  volcanic eruption, like 200 years ago that will cool the planet by several degrees and cause massive crop failures and starvation but there's nothing we can do about that and the next one maybe thousands of years from now. 

If global warming melted all the glaciers and caused the seas to increase 20 feet, it would happen over a 100 year period and everybody would just have to move off of the current coast lines...............over a period of numerous decades.

Higher ocean levels would mainly just threaten humans that decided to build along the coastlines........who would lose their property and need to move. The rest of life on this planet would not get too bent out of shape.

An huge asteroid strike, however could exterminate a lot of humans and a lot of life.........and we can develop the technology to prevent this.

If you look at the moon, you can see all those craters. All of them were caused by asteroid strikes! The earth, being larger has been hit by even more large asteroids!

 Craters on the Moon are caused by asteroids and meteorites colliding with the lunar surface. The Moon's surface is covered with thousands of craters.  Why does the Moon have so many craters compared to the Earth?  

What a great question to ask.

My understanding is that astronomers believe that they've identified all the sizable asteroids that are in orbits that will come close to earth and none them pose a threat of a direct hit for the next many years. They've also identified many of the smaller ones as well, ones that could still do damage but would not be catastrophic. They continue to find and plot orbits for smaller and smaller ones. 

Here is a list of the larger ones with probability of impact https://cneos.jpl.nasa.gov/sentry/

Set the table setting to "Observed Anytime" and the number of entries to 100 to see the full list. Note the first one on the list comes close in 2880 (impact with probability of .00012), with a diameter 1.3 km "bears watching". Of course it's over 800 years away and as time goes by the chances of its impact will get highly refined. Same goes for Bennu  2nd on the list. 

IMHO the danger from an asteroid impact happening any time soon is extremely small and overblown. I think that in all probability, if an asteroid that could do a lot of damage is ever identified to be on collision course, it will be identified with more than enough warning to prevent the collision.

Again IMHO the danger from asteroids is probably orders of magnitude smaller than other dangers facing the planet, e.g. EMP, nuclear war, pandemic, maybe even climate change. Asteroid impact does have a "nice ring" because we could do something about it.

Thanks pj,

I forgot about the threat of nuclear war. That's a biggie compared to the threat of an asteroid strike. Thanks for the reality check on the asteroid threat also.