What is the distance between the Earth and the Sun?

The distance between the Earth and Sun varies from a maximum of 152*106  km at aphelion to a minimum of 147*106 km at perihelion. The average or mean distance is therefore about 149.6*106 km.

If we could ‘fly’, in our imagination, how long would it take to reach the Sun?

At the speed of the Concorde, the fastest passenger plane, it would take less than three hours to fly from New York to London, but to fly a distance equal to that between the earth and the Sun, it would take nearly eight years.

What percentage of the total mass of the Solar System is contributed by the Mass of the Sun?

Over ninety-nine per cent.

Can the Sun ever be seen steadily with the naked eye?

Seeing the Sun steadily with the naked eye will cause permanent damage to the eye except during a total solar eclipse. It can, however, be viewed through special filters which make the Sun appear darker.

At what speed is the Sun moving as it orbits the Milky Way galaxy?

About 275 km/sec.

How long it take the light from the Sun to reach the Earth?

Just under eight and half minutes.