Even though the sun won’t die for another 5 billion years, humans only have about 1 billion years left on Earth because the sun will change and become hot enough to boil and evaporate our oceans.
There is a star in our galaxy that is 5 billion times volume of our sun.
Every second of every day, the sun converts 700 million tons of hydrogen into 695 million tons of helium. The other 5 million tons becomes energy. Every second.
The largest known star is 4,982,686,912 times bigger than the sun, and is only 9,500 light-years away. If placed at the center of the Solar System, its photosphere would engulf the orbit of Jupiter, although the radius is not known for certain and may be larger than the orbit of Saturn.
The sun’s core is so hot that a piece of it the size of a pinhead would give off enough heat to kill a person 100 miles away.
In 1859 there was a coronal mass ejection so intense it shocked telegraph operators and set their equipment on fire. Another such event missed Earth by just 9 days in 2012. Supposedly it was strong enough to take down our entire satellite system and cause significant damage to electrical grids on the ground. One paper even claims that it could have caused $2.6 Trillion in damages worldwide.
The sun and moon appear to be the same size because of an astonishing coincidence: the moon is 400 times smaller but 400 times closer.
Even if the Earth was somehow separated from the Sun, the temperature of the molten core would be high enough to sustain life on the deep sea ocean floor.
The largest known star (per Wikipedia) UY Scuti is 5 billion times the size of the Sun. It would take 2.2 hours to cross its diameter at the speed of light.
If the Sun was scaled down to the size of a white blood cell, the Milky way would be the size of the continental United States.