Although in winter earth is closer to sun in northern hemisphere even then less heating effect of sun is felt on earth. why?

Name the star closest to earth other than sun.

Some scientists have predicted that a global nuclear war on the earth would be followed by a severe 'nuclear winter'with a devastating effect on life on earth. What might be the basis of this prediction?

An aircraft with a wingspan of 40 m flies with a speed of 1080 km/hr in the eastward direction at a constant altitude in the northern hemisphere, where the vertical component of the earth's magnetic field 1.75 xx10^(-5) . Then the emf developed between the tips of the wings is

What remains constant when the earth revolves around the sun?

The motion of earth around the sun is-

How does the heat energy from the sun reaches earth?