Do asteroids have a gravitational field?
I know that asteroids are huge chunks of rock, orbiting a solar system. Do asteroids have a gravitational field and do they gravitationally attract each other to form planets?
@DavidHammen made an important point in a comment on the popular answer: Asteroids do have gravity and billions of years ago that gravity played an important role in the creation of our solar system. However, that gravity no longer appears to play an important role in the universe. Ancient asteroids are now planets and moons or sucked into black holes.
By definition, gravity is a result of mass. Any body with a non-zero mass (even atoms) will have a gravitational field associated with it. The higher the mass the stronger will be the field. This is basic of classical mechanics. Until we reach quantum scale where the gravitational force is dominated by other 3 forces and the gravitational field becomes irrelevent.
When it comes to graitational field of asteroids, it exists, but is very weak. However over a course of few million years these small asteroids combine together to form large masses of bodies that we now call planets. That is one of the prominent theory of Solar system formation, where the gravity of small dust particles from first our generation disintegrated star over a course of time accumulated to give us what we now know as our Solar system.
Think of it like this, every planet that you see now would once have been an asteroid at some point during its evolution.
Another proof to support this is the presence of numerous binary asteroids that orbit each other around a common center of mass, which requires gravitational attraction.
Why so many upvotes for a fundamentally wrong answer? Yes, asteroids gravitate, but then again, so do microscopic grains of dust. The issue with this answer is that asteroid-like objects no longer form to combine larger bodies, and they more or less haven't done so for 4.5 billion years or so. With regard to binary asteroids, the consensus view is that they are formerly larger asteroids that have broken into two objects (or more) thanks to collisions and/or the YORP effect.
I don't get your point, at no point I have said that asteroids are currently forming planets. It's not possible, due to the presence of heavier planets. But being an asteroid would be one the stages of planet formation. wrt binary asteroids I mean their presence tells that they have gravity which is causing them to have an orbit around each other. I have not implied that gravity is responsble for creating them.