Hi, I'm Rachel the Astronomer at the Space Centre.

Around 65 million years ago, the dinosaurs had a terrible day. A city-sized asteroid, travelling at almost 30 times the speed of a rifle bullet, hit Earth and left behind one of the largest known impact craters on Earth – the Chicxulub crater. This chunk of space rock delivered a mind-boggling amount of energy – the equivalent of one million thermonuclear weapons detonated simultaneously – and left behind a crater over 150 km wide.

But while scientists are confident that a giant asteroid crashing into the Earth contributed to wiping out the dinosaurs, they don’t know exactly where the asteroid came from or how it made its way to Earth. A 2007 study using visible light and ground-based telescopes suggested that it could be a remnant of a huge asteroid, known as Baptistina. According to the (now outdated) theory, Baptistina crashed into a main-belt asteroid between the orbits of Mars and Jupiter around 160 million years ago, and the collision sent shattered pieces of rock hurtling towards Earth. Since then, new observational evidence from NASA's Wide-field Infrared Survey Explorer (WISE), a space-based telescope, has ruled out Baptistina as the culprit.

How does WISE search for asteroids?

WISE uses infrared light to detect asteroids. It uses infrared light to determine the asteroids temperature and size, which can then be combined with visible light data from optical telescopes to produce more accurate size measurements.

 

 

 

 

 





Image Credit: NASA/JPL-Caltech/UCLA

These two strings of orange dots belong to asteroids Klotho and Lina. Both orbit in the main asteroid belt between Mars and Jupiter. These asteroids were imaged by NEOWISE, the asteroid-hunting portion of WISE.

So how worried should we be about future asteroid impacts?

Not very! Our current known asteroid count is 958,745. Our first line of defense from asteroids is our atmosphere. If these space rocks are small enough and they get close to Earth, they’ll burn up as they enter our atmosphere. For larger rocks, NASA’s Jet Propulsion Laboratory (JPL) has an automatic detection system in place to keep track of asteroid whereabouts. Every day, observations and orbits of Near-Earth Asteroids (NEAs) are received and processed from the Minor Planet Center (MPC) in Cambridge, Massachusetts. Once confirmed as an NEA, the asteroid’s location and trajectory are automatically updated with JPL’s Sentry system.

More passively, we also have NEOWISE (the asteroid-hunting portion of WISE) that uses measurements of asteroids and comets from WISE images to provide a rich catalogue and archive of solar system objects. NEOWISE data have been used to characterize orbits, numbers, sizes, and probable compositions of asteroids throughout our solar system, and also helped find the first (and only) known Earth trojan asteroid (a tiny, co-orbiting space rock that is tied to Earth by a gravitational leash)!

 

 

 

 

 






Image Credit: NASA/Jet Propulsion Lab-Caltech/UCLA

Earth’s first-known trojan asteroid, 2010TK7 (circled in green) in an image from the WISE spacecraft.

WISE isn’t the only space-based telescope hunting for asteroids. Scientists are using archived images from the Hubble Space Telescope to look for asteroids and they need your help! You can participate in the Hubble Asteroid Hunter citizen science project.

I hope this has inspired you to discover more about asteroids. We’ve pulled together a couple of playlists with some of our favourite web resources to help you learn more about these fascinating rocky remnants of the early solar system.

Go through the playlist at your own pace. Here’s how we suggest you start:

 

Junior Astronomer Playlist (kids 8-12)
TimeActivity
5mins.

Get inspired by watching the Knowledge Network episode about cosmic debris that ends up on Earth with Catch a Falling Star. You have to sign up and log in but it is worth it!

Ask yourself: There are lots of confusing terms. What is the difference between asteroids, comets, meteors, meteorites and meteoroids?

5mins.

Watch this short video about asteroids and comets.

Ask yourself: Can you find other examples of astronomers re-classifying objects in space? (Hint: do a little reading about Pluto – planet or dwarf planet or???)

20mins.

Read this article about why the dinosaurs died.

Ask yourself: Why do you think some animals survived when most of the dinosaurs died after the asteroid hit Earth? If you were a scientist what would you do to find out?

30mins.

Build this paper model of the WISE space telescope. Read more about the WISE mission

Ask yourself: Why do you think astronomers send telescopes into space instead of just using telescopes based on Earth?

60mins.

 

Experiment with water balloons to learn about how asteroids made the Moon’s craters. This is a messy activity and you will need an adult to help, but it is lots of fun.

Ask yourself: If the Moon has so many impact basins from asteroids why doesn’t Earth? Or does it?

Senior Astronomer Playlist (teens 13-15/adults)
TimeActivity
5mins.

Get inspired by watching the Knowledge Network episode about cosmic debris that ends up on Earth with Catch a Falling Star. You have to sign up and log in but it is worth it!

Ask yourself: There are lots of confusing terms. What is the difference between asteroids, comets, meteors, meteorites and meteoroids?

5mins.

Watch this short video about asteroids and comets.

Ask yourself: What kinds of missions are in progress to help scientists learn more about asteroids and comets?

10mins.
- 30hrs.

Build a paper model of one of the space-based telescopes used to search for asteroids. Do your own research to learn more about how each telescope has contributed to our understanding of asteroids.

WISE space telescope (easy)

Hubble Space Telescope (moderately difficult)

Hubble Space Telescope (for experts)
 

Ask yourself: What other types of technology do scientists use to study asteroids?

4hrs.

Watch special programming on June 30, Asteroid Day.

Ask yourself: What was the most surprising thing you learned about asteroids?

hours

 

Become a citizen scientist and help the hunt for asteroids located in archived photos from the Hubble Space Telescope.

Ask yourself: How might this research help contribute to our understanding of asteroids?