A few general questions.

[PrincePhoenix]

1-Does an electron and proton ever meet each other if they are attracted to each other?
2-If yes, what happens when they do?
3-Similarly is the earth getting nearer to the sun due to gravity? I know moon is getting away due to some reasons but what about earth and sun.

[sweet springs]

Hi
1-Usually No. Quantum effect avoids them to meet.
2-But in astronomy high pressure by gravity can make them meet to become neutrons, say neutron stars.
3-I do not know about it and have interest two.

Regards.

[DaveC426913]

1-Does an electron and proton ever meet each other if they are attracted to each other?
2-If yes, what happens when they do?
They can be caused to collide, yes. They combine to make a neutron.
3-Similarly is the earth getting nearer to the sun due to gravity? I know moon is getting away due to some reasons but what about earth and sun.The Moon is climbing away from Earth due to tidal effects. In a nutshell: Earth's imperfect sphere is tugging on the Moon, giving it a kick faster in its orbit. Faster means outward.

This is far, far less pronounced between Sun and Earth. The Sun's tidal gradient is much, much lower. A bigger factor in Earth's orbit is other planets such as Jupiter.

[HallsofIvy]

Well, yes, the getting is getting nearer to the sun! And at a pretty quick rate, right now. It will be closed to the sun in midwinter (in the northern hemisphere) and then start going away from the sun, just like it does every year. The orbit of the earth around the sun is an ellipse, not a perfect circle (though close to a circle- its eccentricty is about 0.0167) so there is a point in its orbit that is closest to the sun and a point in its orbit that is farthest from the sun.

The earth's average distance from the sun does not change much, if at all, from year to year.