8 Astounding Facts About the Asteroid Belt

An artist's conception of the dwarf planet Ceres in the main asteroid belt.
An artist's conception of the dwarf planet Ceres in the main asteroid belt.
ESA/ATG medialab

The asteroid belt tells the story of the creation of the solar system. When it formed, not everything coalesced into a planet. Like LEGO bricks that never made it out of the bucket, these objects were organized by physics into a ring located between the orbits of Mars and Jupiter. This is the asteroid belt. Here are some things you might not know about it.

1. THERE ARE MORE THAN A HALF-MILLION ASTEROIDS.

The asteroid belt in black and white.
iStock

Over a half-million asteroids have been discovered by scientists, with hundreds of thousands yet to be found. They are generally divided into three classes: S-type (for stony); C-type (chondrites, largely composed of carbon, the most common—and perhaps the oldest—of the bunch); and M-type (metallic). The asteroids range in length from 30 feet to 330 miles. For the most part, they are oddly shaped, and, like the planets, spin (though not always so eloquently). Some asteroids have moons; some have two. Not every asteroid is located in the asteroid belt. Some, called Trojans, share the orbit of Jupiter. Some lurk perilously close to Earth. These are called near-Earth asteroids.

2. ASTEROID MEANS "STAR-LIKE."

A night sky with a shooting star.
iStock

The first asteroid was discovered in 1801 by Giuseppe Piazzi, though he didn't know it at the time. He thought he had discovered the long-sought planet between Mars and Jupiter. He named his discovery Ceres, after the Roman goddess of harvest (and namesake to the word cereal, though that word wouldn't be coined until 1818).

Just over a year later, another "planet" was discovered. And another. And another. Eventually, there were so many planets that astronomers threw up their hands and gave the whole group a new classification: asteroid, or "star-like" in Greek. The name was chosen because they appeared, well, star-like in telescopes; they would not resolve as discs as planets do. Ceres's run as a planet lasted about 60 years before it was demoted to asteroid. In 2006, the International Astronomical Union reclassified it again, this time as a dwarf planet. This is the same decision that designated Pluto as a dwarf planet, though there is some debate on this point.

3. ALL THE ASTEROIDS IN IT DON'T ADD UP TO MUCH.

An artists' rendering of the asteroid belt.
iStock

It's likely that illustrations you've seen of the asteroid belt are not drawn to scale. If all of the objects in the asteroid belt were brought together and made into a single ball, its combined mass would only be 4 percent of the size of the Moon. In fact, Ceres alone accounts for one-third of the total mass of the asteroid belt. 

4. FLY YOUR SPACESHIP INTO IT. YOU WON'T HIT ANYTHING.

A little girl plays with a toy rocketship in a space system.
iStock

What’s the biggest misconception that people have about the asteroid belt? Mental Floss asked Dante Lauretta, the principal investigator of the OSIRIS-REx mission to the asteroid Bennu (which once lived in the main asteroid belt before being jarred loose by Saturn and sent on a course for the inner solar system). His response: The Empire Strikes Back. People imagine "that it's this tumbling, highly energetic boulder field with things crashing into each other constantly, and Han Solo has to dodge and weave to avoid collisions," Lauretta says.

But the asteroid belt is downright spacious. If the arcade game Asteroids were real, it would pretty much consist of a ship and a black screen and … nothing to shoot. "When you fly a spacecraft through the asteroid belt, it’s a real challenge to actually get close enough to an asteroid to see it," Lauretta explains. "You have to specifically target it." There are, on average, 620,000–1.8 million miles between asteroids.

5. THE HISTORY OF THE SOLAR SYSTEM IS HIDDEN WITHIN.

An artist's concept of the solar system.
iStock

Back in the 1980s, scientists really set about spectrally classifying each object in the asteroid belt, and they discovered a compositional gradient. There were a lot of dark, carbonaceous objects in the outer asteroid belt, and brighter, "ordinary chondritic," S-type material in the inner asteroid belt. Spectral surveys today are starting to get really detailed, and scientists are getting a good look at objects as small as 6 miles across. As they get into asteroid compositions, they are discovering a fine structure in the compositional pattern, and placing it in the context of the dynamic state of the early solar system.

"Organics and ices are going to be stable farther out [in the belt], and metals and rocks are going to be stable farther in. You expect to see that," says Lauretta. "But now you're starting to see that there really are organic-rich and water-rich materials in the main belt. It's a small fraction of it, but it's a significant fraction. And there's rocky and bright material in the outer belt." That distribution of material is a record of migration of giant planets and the dynamical evolution of the solar system.

"I think we're going to be able to piece together a much more complex, chemical-dynamical coupled model of the evolution of the solar system, and see it almost like the stratigraphic layers of the geologic record. It will tell us the story of the evolution of the belt—not just the initial protoplanetary disk which established that chemistry, but how major events in the evolution of our solar system modified that distribution."

6. SCIENTISTS ARE SEARCHING FOR ITS MOST ANCIENT OBJECTS.

An asteroid in space.
iStock

Presently, planetary scientists are trying to identify and understand the primordial structures in the asteroid belt much in the same way that paleontologists or geologists search for the earliest signs of the origin of life in the geologic record. "That's where the biggest challenge lies," says Lauretta. "There is, in the most ancient examples, a discrete signal that you've got to pull out. It's going to be very tiny."

Scientists endeavor to understand what has been preserved from the dawn of the solar system—what they can trust as a true primordial signature of how our planetary system formed—versus what has been eroded or modified or changed over 4.5 billion years of evolution. "Trying to pick out that starting condition and targeting our scientific investigations into those areas is where the greatest challenge lies."

NASA's recently announced Lucy mission to multiple asteroids will help do this. "Everybody thinks those Trojans are the ones that hold that key to the earliest, most primitive material of the solar system," says Lauretta. "The Lucy team can get out there and do some cool science."

7. ASTEROIDS ARE LIKE SNOWFLAKES.

A snowflake in snow on a dark background.
iStock

No two are exactly alike, and each one has its own story to tell. "Every asteroid is a unique world to explore, and that is awesome," says Lauretta. "There is so much diversity and so many challenges out there. When we truly get out there and start poking around, we're going to see some stuff happening that we never even dreamed of."

8. NASA IS GOING BIG ON ASTEROIDS.

An artist's drawing of Dawn firing its engines above Ceres.
NASA/JPL-Caltech

NASA's Dawn spacecraft is currently in orbit around Ceres, where it continues to characterize that object and how it changes as it circles the Sun. (It previously orbited Vesta, making it the only spacecraft to orbit two extraterrestrial bodies.) NASA's OSIRIS-REx will arrive at the asteroid Bennu in August 2018. Earlier this year, the agency approved two missions to small bodies: the spacecraft Psyche will travel to the asteroid 16 Psyche, a mysterious, all-metal world. (It might once have been the core of a protoplanet.) The Lucy mission will travel to five Trojan asteroids that share Jupiter's orbit. The Japanese Space Agency's Hayabusa 2 spacecraft will arrive next year at Ryugu (a.k.a. 1999 JU3), a near-Earth asteroid. Like OSIRIS-REx, it will take a sample and return it to Earth for analysis.

And that analysis is serious business. In the case of samples and meteorites, Lauretta says, "most people don't realize that we pick apart these things grain by grain, atom by atom, isotope ratio by isotope ratio, and put together detailed stories about what happened billions of years ago in our solar system."

Amazon's Best Black Friday Deals: Tech, Video Games, Kitchen Appliances, Clothing, and More

Amazon
Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Black Friday is finally here, and Amazon is offering great deals on kitchen appliances, tech, video games, and plenty more. We will keep updating this page as sales come in, but for now, here are the best Amazon Black Friday sales to check out.

Kitchen

Instant Pot/Amazon

- Instant Pot Duo Plus 9-in-115 Quart Electric Pressure Cooker; $90 (save $40)

- Keurig K-Cafe Special Edition; $190 (save $30)

- Ninja OS301 Foodi 10-in-1 Pressure Cooker and Air Fryer; $125 (save $75)

- Nespresso Vertuo Next Coffee and Espresso Machine by Breville; $120 (save $60)

- KitchenAid KSMSFTA Sifter with Scale Attachment; $95 (save $75)

- Keurig K-Mini Coffee Maker; $60 (save $20)

- Cuisinart Bread Maker; $80 (save $97)

- Anova Culinary Sous Vide Precision Cooker; $139 (save $60)

- Aicook Juicer Machine; $35 (save $15)

- JoyJolt Double Wall Insulated Espresso Mugs - Set of Two; $14 (save $10)

- Longzon Silicone Stretch Lids - Set of 14; $16 (save $11)

- HadinEEon Milk Frother; $37 (save $33)

Home Appliances

Roomba/Amazon

- iRobot Roomba 675 Robot Vacuum with Wi-Fi Connectivity; $179 (save $101)

- ASAKUKI 500ml Premium Essential Oil Diffuser; $22 (save $4)

- Facebook Portal Smart Video Calling 10 inch Touch Screen Display with Alexa; $129 (save $50)

- Bissell air320 Smart Air Purifier with HEPA and Carbon Filters; $280 (save $50)

- Oscillating Quiet Cooling Fan Tower; $59 (save $31)

- TaoTronics PTC 1500W Fast Quiet Heating Ceramic Tower; $55 (save $10)

- Vitamix 068051 FoodCycler 2 Liter Capacity; $300 (save $100)

- Ring Video Doorbell; $70 (save $30)

Video games

Sony

- Marvel's Spider-Man: Game of The Year Edition for PlayStation 4; $20 (save $20)

- The Legend of Zelda: Link's Awakening; $40 (save $20)

- Hyrule Warriors: Age of Calamity; $50 (save $10)

- Marvel's Avengers; $25 (save $33)

- The Last of Us Part II for PlayStation 4; $30 (save $30)

- LEGO Harry Potter: Collection; $15 (save $15)

- Ghost of Tsushima; $40 (save $20)

- BioShock: The Collection; $20 (save $30)

- The Sims 4; $24 (save $20)

- God of Warfor PlayStation 4; $10 (save $10)

- Days Gonefor PlayStation 4; $20 (save $6)

- Luigi's Mansion 3 for Nintendo Switch; $40 (save $20)

Computers and tablets

Microsoft/Amazon

- New Apple MacBook Pro 16 inches with 512 GB; $2149 (save $250)

- Microsoft Surface Laptop 3 with 13.5 inch Touch-Screen; $1200 (save $400)

- Lenovo ThinkPad T490 Laptop; $889 (save $111)

- Amazon Fire HD 10 Tablet (64GB); $120 (save $70)

- Amazon Fire HD 10 Kids Edition Tablet (32 GB); $130 (save $70)

- Apple iPad Mini (64 GB); $335 (save $64)

- Vankyo MatrixPad S2 Tablet; $120 (save $10)

Tech, gadgets, and TVs

Apple/Amazon

- Apple Watch Series 3 with GPS; $120 (save $79)

- Seneo Wireless Charger, 3 in 1 Wireless Charging Station; $16 (save $10)

- SAMSUNG 75-inch Class Crystal 4K Smart TV; $998 (save $200)

- Nixplay 2K Smart Digital Picture Frame 9.7 Inch Silver; $238 (save $92)

- All-New Amazon Echo Dot with Clock and Alexa (4th Gen); $39 (save $21)

- MACTREM LED Ring Light 6" with Tripod Stand; $16 (save $3)

- Amazon Fire TV Stick with Alexa Voice Remote; $28 (save $12)

- DR. J Professional HI-04 Mini Projector; $93 (save $37)

Headphones and speakers

Beats/Amazon

- Beats Solo3 Wireless On-Ear Headphones; $120 (Save $80)

- Apple AirPods Pro; $169 (save $50)

- Anker Soundcore Upgraded Bluetooth Speaker; $22 (save $8)

- Powerbeats Pro Wireless Earphones; $175 (save $75)

- JBL Boombox; $280 (save $120)

Movies and TV

HBO/Amazon

- Game of Thrones: The Complete Series; $115 (save $89)

- Jurassic World 5-Movie Set; $23 (save $37)

- Deadwood: The Complete Series; $42 (save $28)

- Back to the Future Trilogy; $15 (save $21)

Toys and Games

Amazon

- Awkward Family Photos Greatest Hits; $15 (save $10)

- Exploding Kittens Card Game; $10 (save $10)

- Cards Against Humanity: Hidden Gems Bundle; $14 (save $5)

- LOL Surprise OMG Remix Pop B.B. Fashion Doll; $29 (save $6)

- LEGO Ideas Ship in a Bottle 92177 Expert Building Kit; $56 (save $14)

Furniture

Casper/Amazon

- Casper Sleep Element Queen Mattress; $476 (save $119)

- ZINUS Alexis Deluxe Wood Platform Bed Frame; $135 (save $24)

- ROMOON Dresser Organizer with 5 Drawers; $59 (save $11) 

- AmazonBasics Room Darkening Blackout Window Curtains; $26 (save $5)

- Writing Desk by Caffoz; $119 (save $21)

- SPACE Seating Office Support Managers Chair; $112 (save $116)

- Rivet Globe Stick Table Lamp; $53 (save $17)

- Christopher Knight Home Merel Mid-Century Modern Club Chair; $188 (save $10)

- Walker Edison Furniture Industrial Rectangular Coffee Table; $121 (save $48)

Beauty

Haus/Amazon

- MySmile Teeth Whitening Kit with LED Light; $21 (save $12) 

- Cliganic USDA Organic Lip Balms Set of Six; $6 (save $4)

- HAUS LABORATORIES By Lady Gaga: LE RIOT LIP GLOSS; $7 (save $11)

- Native Deodorant for Men and Women Set of Three; $25 (save $11) 

- BAIMEI Rose Quartz Jade Roller & Gua Sha; $14 (save $3)

- Honest Beauty Clearing Night Serum with Pure Retinol and Salicylic Acid; $20 (save $8)

- WOW Apple Cider Vinegar Shampoo and Hair Conditioner Set; $30 (save $5) 

- La Roche-Posay Effaclar Purifying Foaming Gel Cleanser; $15 (save $5)

- wet n wild Bretman Rock Shadow Palette; $9 (save $6)

- EltaMD UV Daily Tinted Face Sunscreen Moisturizer with Hyaluronic Acid; $25 (save $6)

Clothes

Ganni/Amazon

- Ganni Women's Crispy Jacquard Dress; $200 (save $86) 

- The Drop Women's Maya Silky Slip Skirt; $36 (save $9)

- Steve Madden Women's Editor Boot; $80 (save $30)

- adidas Women's Roguera Cross Trainer; $40 (save $25)

- Line & Dot Women's Elizabeth Sweater; $74 (save $18)

- Levi's Men's Sherpa Trucker Jacket; $57 (save $41)

- Adidas Men's Essentials 3-Stripes Tapered Training Joggers Sweatpants; $28 (save $12)

- Timex Men's Weekender XL 43mm Watch; $32 (save $20)

- Ray-Ban Unisex-Adult Hexagonal Flat Lenses Sunglasses; $108 (save $46) 

- Reebok Men's Flashfilm Train Cross Trainer; $64 (save $16)

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Don't Miss Saturn And Jupiter's Great Conjunction on the Winter Solstice

Paul Williams, Flickr // CC BY-ND 2.0
Paul Williams, Flickr // CC BY-ND 2.0

In 2020, skygazers were treated to meteor showers, a new comet, and a Halloween blue moon. One of the last major astronomical events of the year is set to fall on the night of the winter solstice. On December 21, look up to catch Saturn in conjunction with Jupiter.

What is the conjunction of Saturn and Jupiter?

In astronomy, a conjunction occurs when two planets appear exceptionally close in the night sky. Two of our solar system's gas giants will share a celestial "kiss" on the longest night of the year. The rare meeting of Saturn and Jupiter is known as the "great conjunction" by astronomers.

Though conjunctions between the planets are fairly common, Saturn and Jupiter only get together once in a generation. Their last conjunction happened 20 years ago in the year 2000. Even if you were around for the last one, 2020's planetary meet-up is worth catching. Saturn and Jupiter will come within 0.1° of each other, or about one-fifth the width of a full moon. The last time the two planets came that close was in 1653, and they won't match that proximity again until 2080.

How to see the conjunction of Saturn and Jupiter

Saturn and Jupiter have been inching closer throughout October and November. You can find them now by looking for Jupiter, currently the brightest planet in the night sky, right after sunset. Saturn will appear just east of Jupiter as a dimmer planet with a golden hue.

As autumn wanes, the two planets will gradually bridge the space between them until they reach conjunction on winter solstice. On Monday, December 21, the planets will be so close that they may form a coalescence. That happens when the light from two planets appear to shine as a single star. When that happens, the super-bright body will be easy to spot.