The 10 Best Dino-Killing, Ice Spewing, Earth-Destroying Asteroids

On June 30, 1908, an explosion rocked a Siberian forest.

Eighty million trees were flattened, torn from their roots with their branches sheared off by the force of the blast, according to NASA. No one was killed, but herds of reindeer perished. Scientists have long assumed that the rocky body exploded over the impact site, but, curiously, no debris has ever been found.

In 2007, researchers claimed to have found an impact crater in a nearby lake. More recently, a paper published in March in the journal Monthly Notices of the Royal Astronomical Society suggested something far stranger: that the asteroid that slammed into Earth's atmosphere on that fateful day may have actually bounced off and returned to space.

Behold, the dino-killer.

Sixty-six million years ago an asteroid the size of San Francisco slammed into Mexico's Yucatán Peninsula. A wave of rocky debris shot into the air. A catastrophic tsunami swept across the Earth. The impact sparked massive wildfires and dumped billions of tons of sulfur into Earth's atmosphere, which blocked out the sun, ultimately cooling the planet.

The impact changed the trajectory of life on Earth. As we all know, the effects of this impact were felt for years and years to come. The dinosaurs—and many other type of animals—perished, giving rise to possibly the most dangerous animal of all: us.

On Aug. 29, 1994, the Galileo spacecraft swung past 243 Ida. It was the second time a spacecraft had visited an asteroid, according to NASA. It is also the first asteroid discovered to have a moon.

Ida and its tiny moon, Dactyl, are located in the asteroid belt between Mars and Jupiter and are considered to be part of the Koronis family of asteroids, according to NASA. Like Gaspra, it is an S-type asteroid.

NASA's Dawn spacecraft circled Vesta between 2011 and 2012, collecting a treasure trove of information about the asteroid.

Dawn took pictures of the incredible features on the Vesta's surface including a mountain in the southern hemisphere that stretches higher than Mount Everest and a trio of impact craters that look like a snowman.

Ceres is a world of firsts.

It became the first asteroid ever discovered, when the Italian astronomer Giuseppe Piazzi spotted it in 1801. At 580-miles in diameter, Ceres is the largest object in the asteroid belt between Mars and Jupiter. It's so large that many scientists consider it to be a dwarf planet. Additionally, it's the first object in the asteroid belt discovered to have a spherical shape, carved by its own gravity.

In 2015, NASA's Dawn spacecraft visited Ceres, snapping high resolution photos and collecting data about the strange world. Dawn mapped the surface, spotted evidence of cryovolcanism and identified organic molecules on its surface.

Ryugu, a common C-type asteroid, is the focus of the Japan Aerospace Exploration (JAXA) mission called Hayabusa2. Last year, the spacecraft fired a projectile into the asteroid's surface and captured some of the resulting debris.

Now, it's humming along its journey back to Earth, filled with a treasure trove of cosmic secrets. Later this year, Hayabusa2 will swing past Earth and slingshot a tiny, sample-filled capsule to the ground. There's no doubt that Ryugu will be studied by scientists for years to come.

Bennu is the prime target of NASA's OSIRIS-REx sampling mission. The OSIRIS-REx spacecraft has been studying the asteroid since it arrived in 2018.

Later this summer, the spacecraft will swoop low over the asteroid and scoop up a small chunk for transport back to Earth. It performed a dress rehearsal of the procedure earlier this year. Scientists will have to wait till 2023 before they can get their hands on that sweet, sweet asteroid sample.

The asteroid Didymos and its tiny moonlet companion, Didymoon, are the target of a very important mission. NASA's DART mission will aim to knock the smaller asteroid off course—a cosmic dress rehearsal for when "the big one" comes hurtling toward Earth. It will be the very first time scientists try this method, known as the kinetic impactor method.

The spacecraft will launch in 2021 and will reach the duo a year later. It'll inspect the asteroids and then fire a projectile at Didymoon in an effort to nudge it off it trajectory. Soon after another spacecraft, developed by ESA, will arrive at the asteroids to survey the damage.

Last July, an asteroid the size of a jumbo jet slipped within 222,000 miles of Earth. It was discovered just two days before it was scheduled for its close up. NASA quickly reassured the public that there was nothing to fear.

We've spotted over 20,000 potentially hazardous objects in the solar system, but the close approach of 2019 OD is a good reminder that we still have a lot of work to do.

On April 13, 2029, a 1,100-foot-wide asteroid will swing uncomfortably close to our planet. NASA says 99942 Apophis will sweep within 19,000 miles of Earth, mingling among some of our planet's distant Earth-orbiting satellites.

Discovered in 2004, the asteroid briefly caused a stir when astronomers realized just how close it would get. Researchers suggested at the time that it had a 2.7 percent chance of hitting Earth. Thankfully, finer observations have lowered the stakes.

There's no reason to panic, according to NASA. In fact, it will serve as an incredible opportunity to study an asteroid up close. Let's just hope Apophis—aptly named for the Egyptian "lord of chaos"—will stay far away.

Okay, okay, okay. It's not an asteroid, but we think the comet 67P/Churyumov–Gerasimenko deserves a spot on the list.

The European Space Agency's Rosetta spacecraft visited the comet in Aug., 2014, after a 10-year journey from Earth. For nearly a year, the spacecraft circled the comet, snapping stunning pictures of its gnarled, rocky surface. Rosetta discovered bouncing boulders and, among other wonders, the chemical building blocks of life.

In November 2014, Rosetta deployed the Philae lander, but it bounced into a shadow and eventually lost power, wakening only once, briefly almost a year later. At the end of its mission on Sept. 30, 2016, the spacecraft plunged into the duck-shaped comet.