Below are some sentences in which the sentence numbered 4 has been correctly placed. The rest of the sentences A, B, C, D, E, F need to be arranged correctly in order to form a logical order.

A. But, as it later transpired, by the 1950s, physicists could prove that there is abundant energy in space.

B. Virtually every object in space such as planets, stars, asteroids, and comets are in motion and so there is also kinetic or motion energy in space.

C. Planets, asteroids, and moons reflect that energy back which is why they glow in the dark.

4. All stars in the universe produce energy and transmit it into space.

D. Even though most of the deep space – the vast stretches of empty space between planets, stars, and moons – is cold and dark, space is constantly flooded by electromagnetic energy.

E. They also emit energy from their internal regions in the form of heat from volcanoes or other natural phenomena.

F. Physicists in the early part of the last century were of the view that there is no energy in space since vast stretches of space were dark and empty.