Asteroid Hunters

Front 1

How easy is it to navigate through an asteroid field?

Back 1

Navigating an asteroid field in the main belt (just beyond Mars) is actually super easy and has been done successfully since the 70's. If you take all known asteroids and clump then into a solid mass, it would be smaller than our moon. Space is also so vast that asteroids rarely collide with each other.

Front 2

Where are the majority of asteroids in our solar system?

Back 2

Trojans are asteroids that follow along Jupiter's orbit. The moons of Jupiter and Saturn may have been asteroids that have gotten stuck in the planets' gravity. The Kuiper belt lies just beyond Neptune and there are many more in a region called the Oort Cloud.

Front 3

What is the difference between asteroids, comets and meteors?

Back 3

Asteroids are made of rock or metal, while comets are made of rock and ice. Many asteroids might actually be dead comets, comets whose ice has burned off. When a rock from space travels through Earth’s atmosphere and lands on the ground, we call it a meteorite

Front 4

What was the Cheylabinsk meteor?

Back 4

A meteor event that occured in 2013. It was 20 meters across, and sped through the atmosphere ten times faster than a fighter jet, coming in at a shallow angle. It was moving so fast that the molecules in the atmosphere didn’t have time to get out of the way and built up in a layer of plasma that heated the rock. By the time it was about 38 kilometers (23 miles) above the surface, the heat and pressure was too much, and it burst apart in a series of explosions over four seconds, leaving behind debris and superheated air.Residents saw a fireball speeding above, which briefly became brighter than the Sun, casting its own shadows. They felt the heat from the explosion on their faces, and some noted sunburns. From the city of Chelyabinsk, this explosion was about 53 kilometers away, meaning it took more than two minutes between when they saw the flash of light and when they heard the explosion and felt the shock wave.But although no one was killed, hundreds were injured by shattering glass, and one man lost a finger. Having seen the flash in the sky, many people went to look out their windows at the cloud trail the object had left behind. Unfortunately, many of these people were then injured when the shock wave hit over two minutes later, shattering the windows in over 3,600 buildings.

Front 5

Why do comets have visible tails?

Back 5

Comets get closer to the sun and their frozen CO2 sublimates. This departing gas brings dust with it, creating the visible tails.

Front 6

How many space rocks end up hitting the Earth every day?

Back 6

On any given day, about 90,000 kilograms (100 tons) of dust and small rocks hit Earth. That seems like quite a lot to small creatures like us, but it’s only 0.000000000000000001 percent of Earth’s mass. Most of Earth is covered in water, so most of those objects end up in an ocean somewhere. And even with seven billion people on this planet, there’s still huge regions of land that are uninhabited. But every once in a while one of these objects comes down in a populated area.

Front 7

How big was the asteroid that wiped out the dinosaurs?

Back 7

10 kilometers across. Ten kilometers is about 33,000 feet, which is roughly the cruising altitude of a modern airliner. Imagine a rock so enormous that, resting on the ground, it just grazes the plane’s wingtip. It’s so wide that it takes your plane a minute to fly past it. And it likely would have been moving over sixty times faster than an airplane when it hit.

Front 8

What is the major issue of looking for asteroids on Earth?

Back 8

Since astronomers using telescopes on Earth can only see asteroids at night, this means they can only find asteroids that are currently beyond Earth’s orbit, leaving a blind spot between us and the Sun.

Front 9

How do amateur astronomers find asteroids?

Back 9

To more easily find asteroids, astronomers want to look when asteroids are the brightest—when they are reflecting the most light toward Earth. Like the Moon, asteroids are brightest (or “full”) when the asteroid, Earth, and Sun are aligned. Outside this alignment, part of the asteroid will be in shadow, like a gibbous or crescent moon, and be less bright from Earth. Asteroids are only distinguishable from stars by their motion, so asteroid hunters need to take several images of the same patch of sky to spot an asteroid moving between the stars.

Front 10

How were asteroids named?

Back 10

Asteroid is from the Greek word for “starlike,” because, aside from their motion, they looked exactly like stars through a telescope.

Front 11

Who funds most asteroid finding enterprises?

Back 11

Although there is a vibrant international community of scientists studying and observing asteroids, over 95 percent of near-Earth asteroids have been NASA funded

Front 12

How does the NEOWISE telescope use thermal imaging to find asteroids?

Back 12

Thermal infrared describes how things glow because they have visible wavelengths. Hot things like molten metal or glass are visibly glowing. However, cooler things also glow, just not at visible wavelengths. NEOWISE detects heat from an asteroid , meaning they can also be measured. NEOWISE is in space so that it is kept cold and unaffected by the heat of Earth's atmosphere.

Front 13

What was the effect of a meteor hitting Jupiter?

Back 13

The results were extreme. The first fragment of the comet plunged into the atmosphere at a speed of more than 200,000 kph (120,000 mph), creating a fireball seen by the Galileo spacecraft with a peak temperature of 24,000°C (43,000°F). That’s so hot it’s hard to put into context with things we deal with here on Earth. Even an oxyacetylene welding torch is only 3,300°C (6,000°F). As the subsequent fragments impacted, they rang the planet like a bell, creating enormous waves in the atmosphere that traveled across the planet at 1,600 kph (1,000 mph). They left behind enormous dark spots that persisted for months. The largest dark spot was so large it could fit the Earth inside it, and could be seen with a backyard telescope.

Front 14

What are the three proposed methods of diverting an asteroid and their associated problems?

Back 14

Nuclear blast, kinetic impactor, or gravity tractor (orbiting the asteroid and changing its orbit). Nuclear would only be used to divert its course, but could not blow it up. The size and shape could make this unpredictable. A kinetic impactor would require a lot of mass, and if made from smaller asteroids clumped together the impact could be softened (a bowling ball in a bean bag). A gravitational tug would take years to finesse and also need to be large. You could design one that collects smaller asteroids to increase its mass.