A large asteroid hitting the Earth might be a low-probability event, at least in the near future (over longer periods of time, it's pretty much a certainty), but the damage done could be so high that we have to take it seriously. To help bring awareness to the issue, filmmaker Grigorij Richters and Dr. Brian May, guitarist for legendary arena rock band Queen and and astrophysicist, have co-founded Asteroid Day.
Why is it important? Well, all the efforts that we make to protect the environment, create social justice, and leave a better world for our kids will be for naught if a big enough rock hits us. This almost happened in 1883 when fragments from a billion-ton comet missed Earth by a hair. Impact might be very unlikely, but people buy insurance against all kinds of unlikely things; we can protect ourselves simply by better tracking space rocks and by developing the capability to deflect them.
Starting today, Asteroid Day will take place on June 30 every year in commemoration of the Tunguska event on June 30, 1908, when an asteroid or comet caused a large explosion over Russia, delivering the energy of about 30 million tons of dynamite. That's about 1,000x more than the atomic bomb dropped on Hiroshima... "It is estimated that the Tunguska explosion knocked down some 80 million trees over an area of 2,150 square kilometres (830 sq mi), and that the shock wave from the blast would have measured 5.0 on the Richter scale [...] Different studies have yielded widely varying estimates of the impacting object's size, on the order of 60 m (200 ft) to 190 m (620 ft).," according to Wikipedia.
The Asteroid Day declaration states three goals:
1. Employ available technology to detect and track Near-Earth Asteroids that threaten human populations via governments and private and philanthropic organisations.
2. A rapid hundred-fold acceleration of the discovery and tracking of Near-Earth Asteroids to 100,000 per year within the next ten years.
3. Global adoption of Asteroid Day, heightening awareness of the asteroid hazard and our efforts to prevent impacts, on June 30, 2015.
The project is being supported by top caliber people, including lots of Nobel prize winners and astronauts, as you can see on this signatory page. You can see video message from many of them here. Here's Chris Hadfield:
Now you can't do much directly to help deal with asteroids, but you can help by signing this page to show your support and by spreading the word so that those who can make this happen see that there's support for the idea of better tracking potentially dangerous asteroids and figuring ways to deflect them if needed.
Thankfully, there are some positive things happening on the planetary defense front. NASA and the National Nuclear Security Administration has started working more closely together on this.