Does anybody here know what are the effects of a nova and supernova?
139458
First of all; a supernova and a nova are two different things. A supernova is the violent death of a massive star. A nova is when hydrogen from one star falls onto the surface of a nearby, already dead star, called a white dwarf. This can only happen in a binary system. Also novas happen quite frequently and aren´t very lethal to us. \n\nSupenovas are monster explosions. They are so powerful we can see them even in very distant galaxies. Naturally the effect on us, if a supernova were to go off very close to us say 50 lightyears, would be very very bad. First there would be the radiation. Gammarays, xrays you name it. The ozone layer would be annihilated letting even more radiation, like UV, from the sun in. The whole planet would get a huge dose and things would start dying from radiation poisoning. Afterwards, at of 90% the speed of light, comes the real killers; the highenergy particles. They would bombard every point of the planet like cannonballs, cause mutations and combine with atoms in the atmosphere to form new radioactive elements. Only lifeforms that live deep beneath the sea would stand a chance of surviving as water, lots of water, is the most effective radiationblocker we know. Moving to the bottom of the sea could be a survival strategy for humans but there would be very little warning. Before the radiation and the particles supernovas can be detected by another type of particles; the neutrinos. If we were to suddenly detect neutrinos far beyond what we usually have we can be certain that a supernova is about to pop in a couple of hours.\nDont start building you deep sea shelter just yet though. The closest supernova candidate is Betelgeus in Orion. It´s 427 lightyears away. When it goes(could happen anyday) it would outshine the fullmoon but life on earth would probably survive. If it had been 350 lys closer to us it would be a doomsdayscenario for sure. \nA supernova has probably gone off at the very near proximity of earth atleast once and has possibly caused one of the many mass extinctions life has experienced.
329166
It depends on how massive the star is:\n\nFor stars of less than 8 times the mass of the sun:\nMain Sequence -> Red Giant -> (planetary nebula)-> White Dwarf\n\nFor stars with 8 to about 18 times the mass of the sun:\nMain Sequence -> Red Giant -> (supernova) -> Neutron Star\n\nFor stars with more than about 18 times the mass of the sun:\nMain Sequence -> Red Giant -> (supernova) -> Black Hole\n\nNote that for the massive stars I've simplified things into the "red giant" term, high mass star evolution is pretty complex, and many high mass stars can transition between red and blue supergiants several times during ther brief lives.
936416
you should see the nova on blackholes, it was on last week\n\napprently only to much can actually get to the center at a time, and most matter/energy gets bounced around within the event horizon, never to escape, but not actually getting all the way in\n\nand anyway blackhole emit particles of hawking radiation and would eventually expell there mass and kinda evaporate away\n\nand if one black hole had the whole universe in it, sounds prime for  big bang to me
214416
Life would be hazardous there with jets of positrons from an unknown source and radiation all over the place.\nTowards the center of the galaxy the star population is alot denser than it is out here so there would be a greater risk for a planet there to be exposed to the full blast of a supernova. Supernovas would be devastating to life. It doesn´t matter what elements you are made up of or how many noses you got. The magic ingredient for making life is time. The primordial soup that where the earths oceans was carefully stewed for 800 million years before life developed. In the angry environment that is the center of the galaxy such stability is unlikely to be found.
21091
Correction: when stars "die", they either become a white dwarf (if they're light, where all elements are reduced to primarily iron, which has a lower energy state than anything lighter or heavier--hence, it becomes spent nuclear fuel that cannot react anymore), or a neutron star (as above, but with a mass so great that gravitational forces overwhelm nuclear forces making electron collapse into protons in a single mass), or they can become black holes (if their mass is so very great that all matter is compressed into a singlarity--ie, a point with infite density).  The mass of a black hole is guaged by the degree to which it curves the surrounding space-time continuum.\n\nA white dwarf glows as it is white-hot, but as it cools down, it becomes a brown dwarf, turning dark.\n\nThe debate in astronomy is whether the rate of the universe's expansion is sufficient to keep all black holes from collapsing.  On either end, a break prediction lies: in one scenario, everything forms one big singularity, while in the other, energy fluctations slowly even out until entropy is optimized throughout the universe, resulting in the "heat death" of the universe.
4783
Supernova is formed during the death of stars; large stars and super-large stars. Star dies when nuclear fusion has completed and the core of star will get smaller and smaller. A lot of heat is generated and will heat up the outermost layer of the star. \n\nHydrogen within the layer starts to burn and the stars expands. The star will appear red and are called red giant. Furhter heat loss will cause the stars to collapse because the gravitational force becomes the strongest force. It pulls the star inwards.\n\nIf the red giant is big enough, it will contract so quickly a big explosion called "supernova" will occur.\n\nIt's extremely bright and viewable during daylight. The result, a neutron star if the original star is a large star.\n\nIf it's a super-large star, a black hole will be formed. It's called that because no light can escape it including any matter.\n\nReview other answers about black hole for more details. From what I know, a black hole consumes anything for a long term but it is slowly, very slowly dispersing itself. If you want to wait for a black hole to vanish, you will probably have to wait a million years for it to vanish or you just have to find the best one; the oldest black hole.
701207
it goes super nova and then a neutron star the rest of its life.  its life is also shorter because the increased gravity requires more nuclear fusion (and faster fuel consumption) to negate.
288706
A neutron stars is a dead star, a stellar corpse. Corpses don´t die. They are already dead...\nActually neutron stars are pretty active for a corpse. They spin and send out radiowaves. We call those pulsars and can spin around its own axis in milliseconds. Eventually they spin slower and slower. The faint glow they still emitt because of heat from the gravitational crunch will flicker and fade. This will take many billions of years and the neutrons that made up the neutron star will still be ther. It will just be harder to see than now.\n\nBut there may be more dramatic fates for neutron stars. We know they are the remnants of a type II supernova that occurs when a massive stars die. But there is another type of super nova, type I. Those are even more powerful than a type II. Some evidence suggest that type I supernovas are the result of two white dwarfs (remnants of lighter stars) crashing into each other. There is also no trace of a remnant body after a type I supernova suggesting that the event totally annihilated the white dwarfs that caused it. So what would happen if two neutrons stars collided? It would be one heck of a bang!
276357
A (type II) supernova is the natural end of a massive star atleast 8 times more massive than the sun. The energy for the explosion is generated by a catastrophic gravitational crunch (as opposed to a type I supernova which is an actual nuclear detonation. They are probably caused by two white dwarfs colliding.)\n\nAs a massive star runs out of hydrogen in its core it  contracts and gets hotter until heliumfusion begins. When an average mass star, like the sun, enters this stage it is the end. The core doesn´t have enough mass to fuse elements heavier than helium and a white dwarf remains.\n\nIn heavier stars the fusion processes goes through increasingly heavier elements with the core getting smaller and hotter in each step. When silicone has fused into iron the end has come. Iron is too tighly bound in its nucleus to allow more fusion despite a temperature of 3 billion degrees. With no more energy keeping the core up it collapses with a quarter the speed of light. It shrinks from the size of earth to a sphere only 100 km in diameter in less than one tenth of a second. The gravitational energy released in that instant is 100 times greater than all the energy the sun has put out in all its 4.6 billion year lifetime. Needless to say the star explodes. A super nova is born.\n\nThe core remain however and it contracts so much that, when the core is only 8 km in diameter, protons and electrons cannot exist anymore and you have a neutron star.\n\nIf the mass of the core is greater then 3 solar masses then not even the neutrons can keep the neutron star from contracting further. In stead it shrinks and shrinks and shrinks until the density of the object is infinite. It is now a singularity. We call such singularities black holes because we can´t actually see them. The escape velocity is greater than the speed of light and since nothing can travel faster than light they are truly black. We can only see the effect the gravity of a black hole has on nearby stars.
1079060
http://en.wikipedia.org/wiki/Caffeine#Effects_of_caffeine
235448
It depends so much in what you consider to be an object. If a galaxy is one object, then the largest supernova will be only a very small object compared to it.\n\n\nChandra x ray observatory took images on 2003 of two distant massive galaxies that are between the largest objects scientists have found. \n\nhttp://spaceflightnow.com/news/n0305/21construction/
727897
Supernovas.  Blackholes don't give much back to the universe other than minute sub atomic partices (and not even many of those); similarly with neutron stars.  The sun makes heavier elements like iron, but not the heaviest.
473625
1. the surface is colder than the atmoshpere.\n2. it is about 1/2 of the way through its life span.\n3. its size is such that it could explode as a nova, or just collapse into a white dwarf.\n4. sun spots produce alot of electrical activity, and are a cause of solar flares.\n5. The sun is relatively small compared to most other stars.\n6. The outside of the sun (corona) reaches tempuratures of 27,000,000 degrees fahrenheit.\ni cant seem to scratch my brain for anything more.\nmight i suggest google.com?
566766
A Supernova....i guess.
310303
Usually what happens is a large event such as a supernova will destroy an old star, kicking out elements. Here's how it's believed to have happened before this solar system was formed, since it's believed that the sun is only a 500 million years older than the planets:\n\nWhen a star is about to die, its last stages of life consume a lot of different materials (this is assuming this star is large enough to create a supernova).  When it runs out of hydrogen, it begins to fuse helium, when that runs out, it goes to lithium, then on down the periodic table, until iron, which requires too much energy to fuse, and the fusion within the star ceases.  What happens here is tight . . . lets establish this first:\n\nStars are composed of mostly hydrogen and helium, little bit of lithium, and much much less of the heavier elements . . .  \n\nWhen the iron is left to fuse and it can't be done, the internal pressure from the core, which is generated by fusion, is lost, and the top shell of the sun is left to be supported but, since the fusion pressure has ceased, there's nothing to keep it up, and the outer shell of the star collapses.  This massive collapse of all that material to the leftover core compresses the inward falling material, increasing pressure and when that material hits the inner core, it 'bounces' back out violently, releasing massive amounts of energy, shooting the entire outer portion of the star into space. This is the moment in which heavy elements are made, in supernova events. The universe at one point did not have much by way of heavy elements, but as more and more stars collapse and supernova, they create more and more heavier elements; the origin of the diversity of the periodic table is here.\n\nFrom this you could assume, that as the universe gets older, stars are going to be creating and spitting out more and more heavy elements, and since stars cannot really use heavier elements to fuse, the number of stars over billions of years will slowly start to decline.
1088976
here you go:\n\nhttp://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml\n\nFrom your list it would be nova, but that is for a (relatively) short period of time.
747782
Kentrell, I want you to look at this Nova website, and to watch these videos, OK?  I did, and was quite impressed with them.  they use infrared X-ray telescopes to look to the center of our Milky Way galaxy, with very clear images!!\n\nhttp://www.pbs.org/wgbh/nova/blackhole/program.html\n\nI believe you will like these, will learn from them!