What Is The Difference In Size Between Asteroid And Meteor

What's the Difference Between Asteroids, Comets and Meteors?

Photo of the 2015 Perseid Meteor Shower in the Danish Sky. (Paradigm credit: Ruslan Merzlyakov/<a href="https://www.facebook.com/rmsphotography95">RMS Photography</a>)

In our solar organization there are billions, perchance trillions, of rogue objects orbiting the sun. These spacefarers are as well modest to be called planets and are given the names of comets, asteroids, meteoroids, and if they reach World, meteors or meteorites. With so many labels, it'southward piece of cake to forget which is which.

Permit'southward start with a cursory definition of each.

Asteroids: These are the rocky and airless leftovers from the formation of planets in our solar system. They more often than not orbit our sunday in the asteroid belt between Mars and Jupiter and range from the size of cars to dwarf planets.

Comets: Comets are muddy space snowballs of mostly ice and dust that formed during the birth of the solar system 4.six billion years ago. Nearly comets have stable orbits in the outer reaches of the solar organization by the planet Neptune.

Meteoroids, Meteors, Meteorites: Meteoroids are tiny asteroids or the broken-off crumbs of comets and sometimes planets. They range in size from a grain of sand to boulders iii anxiety (1 meter) wide. When meteoroids collide with a planet'southward temper, they become meteors. If those meteors survive the atmosphere and hit the planet's surface, their remains are called meteorites.

Related: Fallen Stars: A Gallery of Famous Meteorites

Asteroids

At offset glance, asteroids may seem like run-of-the-manufacturing plant infinite rocks, but these ancient solar system remnants come in all shapes, sizes and flavors.

Despite their small stature (the mass of all the asteroids combined is less than Globe'due south moon), asteroids are also called pocket-size planets or "planetoids." They range in size from the smallest boulders, 3 anxiety across (1 chiliad), to the largest asteroid, Ceres, which is most a quarter the size of Earth's moon (about 590 miles in diameter, or 950 kilometers). Ceres is so large, it received a promotion to the status of a dwarf planet in 2006, the same controversial distinction given to Pluto.

Most asteroids look like giant space potatoes, with their oblong shapes and surface that's pockmarked by numerous craters caused past collisions with other asteroids. Simply a minor number of asteroids are large enough that their gravity forms them into spheres, such as Ceres. The composition of asteroids range from dark, rocky clumps of rubble consisting of clay and silicate rocks to bright and solid amalgamations of metals such every bit atomic number 26 or nickel, according to NASA.

About all asteroids are constitute in a doughnut-shaped region between Mars and Jupiter, called the asteroid chugalug. The belt formed not long afterward the birth of Jupiter when the massive planet's gravity trapped planet-forming leftovers, causing them to collide with one another and form the millions of asteroids we run across in the belt today.

Image of more than 100 asteroids captured by NASA's Wide-field Infrared Survey Explorer, or WISE, during its primary all-sky survey in 2014. Clouds of gas and dust surround the region, visible only in infrared light. More than 2,500 stars are also in this view. — Image of more than than 100 asteroids captured by NASA's Wide-field Infrared Survey Explorer, or WISE, during its main all-heaven survey in 2014. Clouds of gas and dust environs the region, visible just in infrared calorie-free. More than 2,500 stars are also in this view. (Prototype credit: NASA/JPL-Caltech/UCLA)

Comets

For millennia, the sight of a comet elicited fear and awe. Ancient astronomers believed comets foretold the death of princes and the outcomes of wars. Modernistic astronomers know comets are the ice-clad leftovers from the fabric that formed our solar system billions of years ago.

Astronomer Fred Whipple was the offset to describe comets as dirty snowballs, or icy conglomerates of frozen gases and dust. The snowball makes up the central nucleus of a comet, which is oftentimes less than a few miles across, according to NASA. When a comet nears the sunday, the nucleus warms up and the ice begins to sublimate from solid to gas. This produces an atmosphere surrounding the comet that can grow to thousands of miles in diameter, called a coma. Radiation pressure from the sunday blows away the dust particles in the coma to produce a long, bright dust tail. A second tail is formed when high-energy solar particles ionize the gas, creating a separate ion tail.

The difference between the composition of asteroids and comets is likely due to how and where they were born, wrote Britt Scharringhausen, a professor of astronomy at Beloit Higher in Wisconsin.

"While asteroids and comets did form at the same time, they did not form under quite the aforementioned weather condition," Scharringhausen wrote. "The solar system formed from the solar nebula, a cloud of gas and grit. At the middle of the nebula, the sun was being born through gravitational collapse. Because of this collapse, which releases heat, the primal regions of the nebula were hotter and denser, while the outer regions were libation."

Asteroids formed near the center of the hot nebula where just rock or metal remained solid under extreme temperatures. Comets formed beyond what's chosen the frost line, where it was cold enough for water and gases similar carbon dioxide to freeze. Considering of this, comets mostly are found just in the far reaches of the solar system in two regions named the Kuiper Belt and the Oort Cloud.

The oddly shaped comet 67P/Churyumov-Gerasimenko. In August 2014, the Rosetta spacecraft rendezvoused and deployed a lander to the comet's surface, a first in history. (Epitome credit: NASA/ESA)

Meteoroids, Meteors and Meteorites

Meteoroids are the truthful space rocks of the solar arrangement. No larger than a meter in size (3.3 feet) and sometimes the size of a grain of dust, they are also small to exist considered asteroids or comets, but many are the cleaved pieces of either. Some meteoroids originate from the ejected debris caused by impacts on planets or moons.

If meteoroids happen to cantankerous paths with a planet'due south atmosphere, like Globe's, they go meteors. The fiery flash given off by meteors when they burn down upward in the temper can appear brighter than the planet Venus, which is why they've earned the nickname "shooting stars," according to NASA. Scientists judge more than 48 tons (43,500 kilograms) of meteoritic material falls to Earth every day. If a falling star survives its descent through the temper and hits the ground, it'southward chosen a meteorite.

When World passes through the trail of debris left past a comet we're treated to the dazzling fireworks display of a meteor shower, where thousands of shooting stars tin can exist seen in the night sky. The Perseid meteor shower is one of the nearly spectacular, occuring every year around Aug. 12. At its peak, 50 to 75 meteors tin be seen per hour if the sky is articulate. The Perseids are caused by the meteoroids broken off from Comet Swift-Tuttle.

These brilliant meteor showers serve equally a reminder that despite the seemingly empty expanse of space, we're more closely connected to our solar system than we imagine.

Additional resources:

Acquire some very strange things most comets revealed by the Rosetta spacecraft, from Infinite.com.
Read about NASA'due south Dawn program, a mission to report asteroids, from Space.com.
Picket this blitheness of all known asteroids and comets in the solar system between 1999 and 2018, from NASA Jet Propulsion Laboratory.