Type Ia supernovae [See Link] follow a characteristic light curve. This luminosity is generated by the radioactive decay of certain elements. The peak luminosity of the light curve was believed to be consistent across Type Ia supernovae as having a maximum absolute magnitude of about -19.3. This would allow them to be used as a secondary "standard candle" [See Link] to measure the distance to their host galaxies

If two stars begin to orbit. However, novae are more common that supernovae, so you can't really say if the result of a binary will be a nova or a supernova.

Anywhere there are massive stars. They are relatively rare events but many have been observed since records began. The first observed Supernova was in 185 in Centaurus and was almost as bright as the moon.

Our closest candidate is IK Pegasi located at a distance of only 150 light years.

When a super-giant star explodes it shines brighter and turns into a supernova.

about 27 thousand

by Kenny cheung

That is a rediculous answer.

The current Guide Star Catalogue (GSC-II) contains 945,592,683 stars out to magnitude 21. That's almost a billion.

a supernova is an explosion, a moving event, so it's diameter is time dependant.

Loud is a relative term used in hearing depending on what object is doing the hearing and what frequency range. For example, what is loud to dogs would be silent to humans if the sound is outside of the human hearing bandwidth 100-20,000 Hz. Loud for humans would be generally described as passing the pain threshold of hearing.

Nova (plural novae) means "new" in Latin, The prefix "super-" distinguishes supernova from ordinary nova.

When a star explodes as a supernova, it has finished it's main sequence, is in maturity and when it finally explodes it's in the stellar remnants stage.
A white dwarf star is capable of turning into a supernova if the fusion action is reignited. It can also happen when a star starts to collapse.

There are some effects of UV radiation that might mutate your face but the closest star is so far away it probably wouldn't have much effect at all. Our Sun will never go supernova but if it did, in this situation you wouldn't want to be anywhere in the solar system none the less turn to look at it.

The rapid collapse of the star compresses atoms together and may cause nuclear fusion and make heavier elements.

Multiple questions.

See related questions.

Sometimes. It depends on the precise conditions. The mass of the star (after blowing off its outer layers in the supernova) has to be at least 1.5 - 3 times the mass of the Sun in order for it to collapse into a black hole.

The remnants of a smaller star (but still larger than the sun; the sun is too small to become a supernova) will probably stop collapsing after the supernova at the neutron star stage.

From 1400 BC to AD 1600, China recorded around 90 novas. Among them the supernova SN1054 [See Link] was the first supernova confirmed by modern radio astronomers. A British astronomer in 1731, discovered an oblong cloud"" over China. After observation, calculation and analysis by several astronomers, it was proved that the crab shaped nebula found in this position was the ruins of a supernova that had shot out of a dense cluster some 900 years previously. i.e. the year of 1054. This discovery was one of the most significant astronomical findings in the 1960s.

The phenomenon that occurs when massive stars explode is a supernova. This happens to stars that are more massive than the sun. They are called hypergiants. In such a star, the core collapses leading to the explosion.

Depending on the mass of the original star, a supernova explosion may cause a neutron star (for medium to large stars) or a black hole (for large or very large stars). If the original star was rotating fairly rapidly, the neutron star may be a "pulsar", the name given to a rapidly spinning neutron star that emits pulses of X-rays. "Rapidly" spinning in this case is upwards of three revolutions per second.

Unlikely. it has been proposed to explain away the Star. Some stars are unstable and explode in this way with a bright blaze. However, historical records do not indicate a supernova at this time.

Some stars explode as supernovae when they run out of the hydrogen which they depend on to stay hot. Another way is due to binaries - when a particularly large star, e.g. a red giant, attracts a smaller star due to gravitational pull, and they orbit each other. The star cannot bear the heat and explodes in a massive amount of heat and light - that is how novae happen. A supernova has a much larger effect than a mere nova, and they happen when the star collapses due to reduction of fuel before the spontaneous explosion, and thus causing it to be much larger and brighter.

First, a supernova is a stellar detonation. It exists for a very very short time. In effect, it is a white dwarf (ie: exposed star core) with a nebula rapidly retreated / expelled from it.

As for the remainder of the question, categorically speaking the answer is black hole.

That said, a black hole can be so small (in size) that despite its mass it would have little or no affect even if it passed right through you. Some theorists have spoken of pseudo-hydrogen, basically a black hole with an electron captured in orbit about it. However, such would never last long due to Hawking radiation (the means by which black holes evaporate over time). Likely many such were created during the Big Bang and have long since evaporated. Some might even be created in the largest particle acceleraters of the future, but they too would evaporate before leaving the lab. Well, a supernova has more push than pull when it occurs, and a white dwarf is too tiny to have too much of a pull and the black hole actually has the biggest gravitational pull in the universe! Well for humans know that is.

Massive stars.

See related question:

2nd Answer:

Yes, massive stars, but ones with another star like a red giant orbiting each other.

The to-be supernova 'sucks' material from the other star near it until its mass is large enough to make the star collapse and burst.

On average, supernovae occur about once every 50 years in a galaxy the size of the Milky Way.

However, there are an estimated 100 billion galaxies.

The reason we don't see them all the time, is the shear distance from Earth and the time it takes light to reach us.

See related for information about a supernova

A red giant, otherwise the star that is dieing will just shrink into a white dwarf and eventually disappear.

Its not big enough. You have to have a certain amount of mass to end as a supernova.