# How big? **URL:** \ **Category:** Factual Questions\ **Created:** [April 18, 2003, 2:09am UTC](https://boards.straightdope.com/t/how-big/169464 "2003-04-18T02:09:49Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [April 18, 2003, 2:09am UTC](https://boards.straightdope.com/t/how-big/169464/1 "2003-04-18T02:09:49Z")
I was reading [this thread,](http://boards.straightdope.com/sdmb/showthread.php?threadid=178041)when a thought errupted in my mind: How big can an asteroid be? What’s the largest mankind has witnessed (via hubble, or other instruments)? Could a asteroid be as large as our galaxy? If so, what would happen if it came crashing through our galaxy? I’d imagine that the effects of the gravitational pull would effect us long before we actually saw the asteroid, is this true? ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [April 18, 2003, 2:27am UTC](https://boards.straightdope.com/t/how-big/169464/2 "2003-04-18T02:27:11Z")
> [@](#): > > Most asteroids are made of rock, but some are composed of metal, mostly nickel and iron. They range in size from small boulders to objects that are hundreds of miles in diameter. A small portion of the asteroid population may be burned-out comets whose ices have evaporated away and been blown off into space. Almost all asteroids are part of the Main Asteroid Belt, with orbits in the vast region of space between Mars and Jupiter. Source: [http://impact.arc.nasa.gov/](http://impact.arc.nasa.gov/) > [@](#): > > Asteroids are rocky and metallic objects that orbit the Sun but are too small to be considered planets. They are known as minor planets. Asteroids range in size from Ceres, which has a diameter of about 1000 km, down to the size of pebbles. Sixteen asteroids have a diameter of 240 km or greater. They have been found inside Earth’s orbit to beyond Saturn’s orbit. Most, however, are contained within a main belt that exists between the orbits of Mars and Jupiter. Some have orbits that cross Earth’s path and some have even hit the Earth in times past. One of the best preserved examples is Barringer Meteor Crater near Winslow, Arizona. > > Asteroids are material left over from the formation of the solar system. One theory suggests that they are the remains of a planet that was destroyed in a massive collision long ago. More likely, asteroids are material that never coalesced into a planet. **In fact, if the estimated total mass of all asteroids was gathered into a single object, the object would be less than 1,500 kilometers (932 miles) across – less than half the diameter of our Moon.** Source: [http://www.solarviews.com/eng/asteroid.htm](http://www.solarviews.com/eng/asteroid.htm) ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [April 18, 2003, 2:34am UTC](https://boards.straightdope.com/t/how-big/169464/3 "2003-04-18T02:34:37Z")
😃 Definition of “asteroid”. > **[Asteroids: What and Where Are They?](https://www.thoughtco.com/asteroids-and-the-asteroid-belt-3073446)** > > An easy exploration of asteroids in the solar system and the Asteroid Belt region where many exist in orbit around the Sun. > [@](#): > > Definition: Asteroid; A rock in space that can be sized between a few feet and several miles wide. Most asteroids in our solar system are part of a belt between Mars and Jupiter. > > Also Known As: Planetoid If you’re talking about something that’s “as big as a galaxy”, then it wouldn’t be an “asteroid” any more. Dunno what it would be, probably a “rock galaxy”. As for the biggest asteroid/planetoid found so far, it’s a thing called Quaoar, out in the Kuiper Belt. [http://www.cnn.com/2002/TECH/space/10/07/ice.object/](http://www.cnn.com/2002/TECH/space/10/07/ice.object/) ---
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [April 18, 2003, 3:06am UTC](https://boards.straightdope.com/t/how-big/169464/4 "2003-04-18T03:06:48Z")
Okay, so it’s not an asteroid… Anyone know what it _would_ be called? A reallyreallybigoid? 😃 ---
**Author:** ![AncientHumanoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ancienthumanoid/32/278_2.png) [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)\ **Post date:** [April 18, 2003, 3:14am UTC](https://boards.straightdope.com/t/how-big/169464/5 "2003-04-18T03:14:18Z")
> [@](#): > > \*Originally posted by Meatros \* > \*\*Okay, so it’s not an asteroid… > > Anyone know what it _would_ be called? > > A reallyreallybigoid? 😃 \*\* You bet your ass-teroid. 😛 ---
**Author:** ![Joe\_Random](https://avatars.discourse-cdn.com/v4/letter/j/e8c25b/32.png) [@Joe\_Random](https://boards.straightdope.com/u/Joe_Random)\ **Post date:** [April 18, 2003, 3:18am UTC](https://boards.straightdope.com/t/how-big/169464/6 "2003-04-18T03:18:45Z")
> [@](#): > > \*Originally posted by Meatros \* > **Could a asteroid be as large as our galaxy?** I doubt that _any_ solid object could be that big. It’d collapse under it’s own gravity, most likely into a black hole.