It sounds like you might be describing a supernova, which is an astronomical event where a star undergoes a powerful explosion, briefly outshining an entire galaxy before fading from view. Supernovae can result from the death of massive stars or from the interactions in binary star systems.
A very reactive metal can react too violently with acids to be safe.
A star is a ball of gas that is very hot and very bright.
A nova is a star which has a close companion star, and draws stellar material off of it's companion, occasionally flaring up very brightly in the process. A supernova is a massive and hot star to begin with, that tends to go through it's life cycle at high speed, and ending it's life in a cataclysmic explosion. Supernova remnants then collapse into a neutron star - a spinning, very hot pile of stellar ash, so dense that a teaspoonful of it would weigh thousands of tons. If the collapsed supernova star was big enough, it's gravity upon collapse is so intense than not even light can escape from it, and it becomes what is called a "Black Hole".
The sun
Comets are very cold objects with no atmospheres and very weak gravity. When they go close to the sun the violently eject jets of gas.
After a supernova of a very massive star, the core collapses to form either a neutron star or a black hole. The outer layers of the star are ejected into space, enriching the surrounding environment with heavy elements. A bright burst of radiation, known as a gamma-ray burst, may also be emitted during this process.
Magnesium is an element that burns very brightly when ignited, producing a brilliant white light.
No, a meteor is a small piece of space rock that burns very brightly and with high temperature as it passes into our atmosphere at high speed.
No. Stars of different sizes and composition have different luminosity (light) levels. A very big star will most likely be blue and shines very brightly, while small stars like white dwarf stars emit very white light, but are mostly very dim.
sodium sodium
Usually White or very brightly colored.
predators can easily spot them.
Gem
At very high temperatures, atoms and molecules in a substance shake violently due to increased thermal energy. This can cause particles to move rapidly and collide with each other, leading to an increase in kinetic energy and temperature.
Yes, it reacts with the oxygen in the air and water very violently.
Yes, It reacts very quickly and violently.
no, there is no blood i think, and they die very non-violently