I recently went to my daughter’s school in order to make a 3 hour presentation about space. I took with me my laptop, a projector, photos, video sequences, illustrations and paper models on famous satellites and robots that human beings used during the Gemini and Apollo era back in the sixties and seventies. And believe me I was surprised by how much these 8 years old kids knew in advance!
One of the first questions that popped was, “What about comets, meteors and black holes?”. The kids where in need to know about the outer threats, a threat caused not by humanity itself, not by the nature on earth but about a threat coming from outer terrestrial flying objects within the inner solar system. They were fascinated on how threats from far away could cause such devastation. I tried to avoid scaring the kids by telling them about the consequences of these threats. I will tell you how I responded later.
Aftonbladet, a Swedish newspaper published an article today (Nasa kan inte skydda jorden – “NASA cannot protect the earth”) about space and this time in particular they thought of writing about NASA’s NEO (Near-Earth Objects) program. It is certain that the budget in the US is currently restrained within many levels of the departments in the government. It is rough times for US economy and that has a great impact for NASA projects as well. History repeats itself, if we bring up Apollo missions as an example. Been there, done that, dont need that anymore!
Despite threats from budget cuts, the NEO program actually made some remarkable progress. It takes a great deal of time and sophisticated equipment to detect, analyze and catalogue tiny objects in space and scientists need to re-analyze these objects several times in order to detect their velocity and direction in order to predict future movements near earth.
We also have to remember that astronomy’s terms regarding distances and time are enormous in comparison to the timeframes and distances used in daily life. When an astronomer is talking about “Recent events” then she could be talking about hundreds of millions of years back in time. Or the term “close encounter” would be if a rock passes far away and behind the path of our moon. Remember that Apollo ships took 4 days to reach the moon travelling at the speed of a bullet!
In history, impacts that threatened life on earth have actually occurred. It is confirmed and well documented both from Apollo expeditions and by scientists on Earth. We also know that these kinds of impacts ending life will with all probability occur again. The question is rather “when” than “if” and if we think statistically about the time between these events it is currently believed that they occur more or less 20 million years apart. Statistically and theoretically we are currently quite close to an impact event – but nothing is certain. It may happen in 100 years or in 1000.
Again, astronomy is dealing with vast distances. Outer solar system members, such as the gas giants Jupiter and Saturn, are our defence. Due to their large mass, stones are often pulled into their gravitational field before reaching Mars or Earth (ex. is Shoemaker-Levy 9 comet).
So all in all, things called “soon” or “close to us” are still very far away and most likely will not occur during our lifetimes.
Back to my daughter’s class: when I saw the importance of giving a good answer, I told them threats from these objects are not going to affect us during our lifetimes. And by the time humanity will face these threats our technology will be far more advanced and we will be able to deal with these rocks!
Enjoy the sight of Perseids that can be seen out in the summer night as we speak. They will only last for a couple of days and it is a beautiful event. Unfortunately the weather in the south regions of Sweden has not allowed me to see them yet.
- Aftonbladet’s news article (In Swedish) – http://www.aftonbladet.se/nyheter/article5636367.ab
- NASA NEO program