Would Earth's orbit change if the Sun were replaced by a rock of the same mass?

[aerogurl2]

I am having trouble understanding the concept of the effects on an orbit. The question asks if we replaced the sun with a rock of the same mass, would Earth's orbit change? I think it doesn't because orbits don't change because of its orbital energy. but I'm not sure because i wonder if the kinetic and gravitational energy would change and thus affect the orbit?

 

[Dick]

What effect keeps the Earth in orbit?

 

[aerogurl2]

i thought orbital energy keeps it in orbit

 

[Dick]

Wrong. A force keeps it in orbit. Not an energy. Which force?