There is an authentic Hadith (Muslim - Tirmidhi) regarding the heat of doomsday. 

Miqdad bin Aswad (ra) narrates:

“The Rasul of Allah (saw) said:

‘During doomsday the sun will be brought near to mankind until the distance between them is equal to a mile.

The heat of the sun will almost melt them and the people will begin to sweat according to their deeds. Some up to their hills, some up to their knees, some up to their waste and some will drown in their sweat!’

Soloman bin Amr (ra) who narrated this Hadith also added, ‘I don’t know if the word ‘mile’ was used in reference to the unit of distance or the stick used to apply kohl to the eyes (meel)’.”

In truth, it does not really matter which was intended, the results remain the same.

This is a miracle!

Think of the level of knowledge of the people of Mecca 1400 years ago. While most of the people in the world at that time were thinking the earth is flat with no substantial knowledge about the sun and its nature, the Rasul of Allah claimed:

“The sun is going to envelop the earth such that there is only going to be a mile between them!”

Most people aren’t even aware of this truth today!

Here is another Hadith from Bayhaki:

Ibn Masud (ra) narrates from the Rasul of Allah (saw):

“When the people are resurrected they will wait with their eyes fixed on the sky for forty years. Nothing will be said to them. The sun will be right above them and it will burn them. Everyone, good and bad, will wait in this state with sweat up to their heads.”

Those who claim on doomsday the stars are going to fall from the heavens and the sun is going to black out are proven wrong with this Hadith. The sun will black out many years after it becomes a giant red star and shrinks to become a dwarf neutron star. This process occurs long after the period of doomsday. 

This Hadith clearly verifies the science that the sun will eventually engulf the earth yet we are still looking for a hell in some imaginary faraway place!