Scientific Hadith About temperature and color

Prophet Muhammad said that the hell fire was burned for thousand years until its color becomes red then it was more burned for thousand years until it becomes white and then at last hell fire color becomes dark black.

"The Fire was kindled for one thousand years until it reddened, then it was kindled for one thousand years until it whitened, then it was kindled for one thousand years until it became blackened, so it is dark black."Jami’ at-Tirmidhi (2591)

Today we know that the color of fire depends on that how hot it is. Firstly on lower temperature its color becomes red then on more temperature it becomes white and at very high temperature it becomes dark black.

 In Another Hadith prophet Muhammad said that the hell fire is 70 times more hot than the worldly fire . 

Abu Huraira reported: The Prophet, peace and blessings be upon him, said, “Your fire, which the son of Adam ignites, is only one of seventy parts from the fire of Hell.” They said, “By Allah, that would be enough, O Messenger of Allah!” The Prophet said, “Verily, it exceeds it by sixty nine parts, each of which are like its heat.”Source: Ṣaḥīḥ Muslim 2843

The worldly fire is 1100 degree Fahrenheit if you multiply it by 70 times you will get 77000 degree Fahrenheit . Today We know that at this temperature a fire would appear black .

The brightest star in the night sky, Sirius has a surface temperature of about 18,000 degrees F, which gives it its bluish tinge.But there are other stars, invisible to the naked eye Because space color is black, which are far hotter than Sirius.

(Source: astronomer Bryan Gaensler On scientificamerican.com). An Object At 77000 degree Fahrenheit That star would be invisible in space because space color is also black and the fire color would be black.