What are the advantages of using a blue flame instead of a yellow one for heating objects in the laboratory? The blue flame burns cleaner and heats better than the yellow one.

A blue flame colour means complete combustion. This indicates that the gas is being burned efficiently without any unburned and wasted gas. With complete combustion you get the maximum heat output from your gas and use less gas to generate heat with whatever appliance you are using.

Cygnus X-1 is the heaviest stellar black hole observed without using gravitational waves. The famed Cygnus X-1 black hole (illustrated, slurping mass off its companion star) is nearly 1.5 times as massive as astronomers thought, new observations suggest.

After just a few minutes more — 21 to 22 minutes total — the entire mass of the Earth would have collapsed into a black hole just 1.75 centimeters (0.69”) in diameter: the inevitable result of an Earth’s mass worth of material collapsing into a black hole. When matter collapses, it can inevitably form a black hole.

Although quasars are known to drive strong winds and jets of relativistic particles that can be dangerous in their own right, Forbes and Loeb looked at the damage caused by their light alone.

Judging from the number of stars large enough to produce such black holes, however, scientists estimate that there are as many as ten million to a billion such black holes in the Milky Way alone.

Black holes swirling with stars But the majority of black holes in our galaxy are invisible, so the only way to find them is by observing their gravitational effects on surrounding objects. The astronomers studying HR 6819 weren’t looking for black holes at all.

A supercluster is a large group of smaller galaxy clusters or galaxy groups; it is among the largest known structures of the universe.