at this stage, is there any serious potential hazard for our planet from outer space?

Question

comets, asteroids etc.

Answer 1

I would say at this point no. It is well within our capabilities to determine whether or not we could be hit by an asteroid about 1km in diameter or larger within the next 100 years. However the rough probability of this happening assuming we knew nothing about the positions of what is out there is only of the order of 1 in 100,000. Thus the effort really only takes us from saying that there is a 99.999% chance that we won't be hit to saying we are 100% certain we wont be hit.

At present we have catalogued around 700 to 800 objects around 1 km in diameter and the total population is estimated at around 1,100. We have quite good observational data on most (80%) of the ones we've catalogued which means we have a good idea where they will be into the future and know when we can get more data to further hone our predictions.

There are a lot more objects out there that are smaller than 1km in diameter so we are much more likely to get hit by them. Being smaller they are also harder to detect and surveys to find them cost more money. The present search has got by with around $4million per year for the last 9 years from NASA, money from US defence agencies, other contributions from governments and foundations and considerable effort from amateur astronomers. Budgets for bigger surveys such as Pan-STARRs and the LSST run into the hundreds of millions of dollars and the recent NASA NEO report suggested a budget of about $1billion to find most of the hazardous objects bigger than about 100m (estimated number 20,000) over the next 20 years.

At the low end of the scale we probably get hit every year on average by an object about 4 m in diameter, which mainly goes unnoticed except for a loud bang. We also get hit all the time by small grains of dust.

The JPL NEO web pages and the NEODys pages (based in Pisa in Italy) contain data on the objects found to date and also present risk information in the form of estimated probabilities of collisions by specific objects about 100 years into the future. The IAU Minor Planet Center is the main clearing house for data and also shows orbital plots, close approach calculations and the like.

Answer 2

I am very enthusiastic about your use of the phrase..."at this stage."

We can rest fairly easy knowing that nothing major will strike the earth within the next few years. That indication has been given out as a report by NASA deep space observers. However, since Asteroids have no illumination of their own (they are not stars) they are also very hard to "see." So there is a possibility that one can slip by undetected. So, while we might say with relative certainty that we are safe, there is always a small chance of error. As you push the time envelope out by years and years, the degree of uncertainty obviously increases.

Answer 3

No. But we are likely to destroy ourselves before anything destroys us. In the late 1980's there were many magazine articles claiming that comets and large meteors would hit the earth between 2000 and 2004. Those years came and passed without anything happening. The stories about large scale comet strikes are just sensational publications which usually lack any scientific backing.

Concentrate your worries on real dangers such as deforestation, pollution, child abuse, rape and war. These small things are within our control and they will definitely destroy mankind if we do not stop them.

Answer 4

Comets, asteroids etc.
Solar storms
Grumpy aliens with large weapons...
Planet X making a bypass and it's grvitational pull causing havoc...
Human space based weaponry...
I'm sure we're capable of proving hazardous enough on our little ownsome!...

Answer 5

I think it is totally unpredictable. Any major change happening in some corner of the universe can have ripples and can probably affect our planet. Unless we know how the whole of universe works as a system nothing can be predicted. But then why worry about it?? with so much of advancement in science and medicine, still nobody can predict anybody's death on earth.........why worry about something totally out of our control??????

Answer 6

Eventually something big will hit us, but right now we are at more risk from ourselves in the form of nuclear annihilation, with a distant second being biological extermination.

I have read that we would have 2 years notice if anything big was flying directly at us.

Answer 7

I have a newpaper cutting stating that on Feb 3rd 2019 at about 9am the world will END (maybe)...

...This is due to a huge rock travelling at 60,000 miles per seconds that has a 1/1,000,000,000 chance of hitting us... I'm not being funny but the chances of hitting the jackpot on the lottery are BIGGER! so I don't like our chances!

Answer 8

Do not worry. There is no hazard from outer space. It is we, human beings, who will be responsible for the hazard of earth.

Answer 9

Yes, there are big asteroids on trajectories that will have them cataclysmically impact the Earth, as they have routinely done in the past. So what?

Answer 10

Not at the moment, but in the Future who knows.