This image from MRO’s High Resolution Imaging Science Experiment (HiRISE) camera, obtained on 9 May 2014, shows the new double crater. The larger crater is ~48.5 meters across and is the largest and newest known impact crater in the solar system.

We’ve also been recording instances of recent asteroid collisions with Earth – this map shows at least 556 collisions of small asteroids with Earth from 1994-2013. The map shows that small asteroids, with sizes of only a few meters, hit the atmosphere and disintegrate with surprising frequency - around every other week. The color of a dot indicates whether the impact occurred during daylight or nighttime hours, and the size of a dot indicates how much energy was released by the impact. Keep in mind that Earth’s atmosphere does a good job of protecting us from these small objects, while the Moon and Mars don’t have a similar sort of protective shield.

This diagram plots data gathered from 1994-2013 on small asteroids that impacted Earth’s atmosphere and disintegrated to create very bright meteors, technically called ‘bolides’ and more commonly referred to as ‘fireballs.’ The sizes of the orange dots (daytime impact events) and the blue dots (nighttime impacts) are proportional to the energy released in the impact and show the location of impacts from objects ~1 to 20 meters in size.

While we know that small asteroid impacts with Earth are not unusual, the risk of future, possibly larger, impacts is not to be taken lightly. "The aim is to find potentially hazardous asteroids before they find us," as asteroid expert Don Yeomans has said.

Every day, Earth is bombarded with more than 100 tons of dust and sand-sized particles from space. About once a year, an automobile-sized asteroid hits Earth's atmosphere, creating a spectacular fireball (bolide) event as the friction of Earth's atmosphere causes them to disintegrate.

Studies of Earth's history indicate that about once every 5,000 years or so, on average, an object the size of a football field hits Earth and causes significant damage. Once every few million years, on average, an object large enough to cause regional or global disaster impacts Earth.

Bolide over the Gulf of Mexico as seen from the ISS (Expedition 30) in March 2013. Thunderstorms and lightning can be seen over the Florida peninsula.

Most terrestrial impact craters have been obliterated by weathering and geological processes. Meteor Crater near Winslow, Arizona, is one spectacular example of a crater that remains very visible. It was created by the impact of an estimated 50-meter sized asteroid about 50,000 years ago. This feature, 1.2 kilometers (almost a mile) in diameter, is the first that scientists recognized as an impact crater.

Meteor Crater, Arizona imaged from the International Space Station (during Expedition 44). The squarish, box-like appearance from above may be the result of geological features at the impact site.

Since Meteor Crater was identified, aerial and space-based observations and subsurface excavations have discovered a total of 188 craters on Earth, so far. We’re still looking.

The morphology, or form, of impact craters differs depending on size. Smaller impact craters, up to 4 kilometers in diameter, have a bowl-shaped form – like Meteor Crater. We call them simple structures. Complex impact craters, 4 kilometers or larger in diameter, have central uplifted features in the form of peaks or rings, and slumped rims. These two basic types of crater morphology have been observed throughout the solar system, including on Earth.

LRO image of Tycho Crater clearly shows the central peak and a broad ‘flattened’ floor surrounded by slumped, terraced walls. Surveyor 7 landed just northward the crater rim.

Gosses Bluff Crater in located in the southern part of Australia’s Northern Territory and is representative of a complex crater on the Earth. Approximately 3 km across, this is actually the inner ring remnant of the original crater. Earth’s erosional processes have erased the outer rim, which probably would have been ~20 km in diameter. Expedition 44 crew photographed Gosses Bluff in 2015.

The International Space Station completes one orbit of Earth every 90 minutes. ISS is at an orbital inclination of 51.6° with respect to the equator, enabling the station to pass over vast swaths of our planet. Manicouagan Crater, located in the Côte-Nord region of Quebec (51° 23’ north and 68° 42’ west), was created when a ~5 km diameter asteroid impacted the planet roughly 215 Myr ago. Manicouagan is a multi-ring structure, 100 km across, making it the sixth largest confirmed impact crater on Earth.

Meteor Crater taken by Expedition 38 crew. North is to the upper right. I-40 highway nearly bisects the image. Winslow, Arizona is located at the bottom center of the image. The object that excavated the crater about 50,000 years ago had an iron-nickel composition and was roughly 50 meters in size.

Roter Kamm Crater in Namib Desert, southern Namibia as imaged by Expedition 38. The crater is ~2.5 km in diameter and was formed perhaps ~4 to 5 million years ago. The crater is about 130 meters deep but, sand has filled the crater floor.

Expedition 40 views Shoemaker Crater.