So the sun explodes in a supernova: What would we see from Earth?

Question

Here are the details:

Light travels at 299,792,458 m/s (the fastest speed that ANYTHING can travel), and the Earth is 150,000,000,000 m (1 Astronomical Unit) from the sun.

If the sun were to go supernova (i.e. explode), what would we see from Earth? From my albeit rudimentary calculations, we would see---for approximately 5 seconds (derived by dividing the distance between us and the sun by the speed of light)---the sun either exploding or growing extremely large (into a red giant) before we would be completely obliterated. And what a 5 second fireworks display it would be!

Can anyone back this up or offer a different argument?

My bad... I calculated wrong... There would be approximately 500 seconds (8 minutes or so) before all hell broke loose. Thanks to all those who noticed the error... Keep those answers coming!

Answer 1

i'm reminded of the bomb- tech and his assistant working on the first nuCLEAR weapon....the kid said," what if it goes off ?"

Tech said , " we'll never know ..."


use plenty of sunblock.

Answer 2

You are off by a couple of digits. Light from the sun takes 500 seconds, or a little over 8 minutes, to get to earth. Not 5 seconds. Nor will the sun ever go supernova. If the sun was massive enough to become a supernova earth would reside within a red supergiant. And so would saturn!
Anyway, if some evil alien race came along and decided to wipe out humanity by making the sun go supernova with some gravity weapon then we would see light. Lots of light as the sun would suddenly increase in brightness 100 million times... Forget about sunblock. It won´t do a lick of difference.

Answer 3

Well, there is one thing for certain...

None of us, or any humans will ever see this tremendous explosion in the Solar System. Life on Earth is poised on a very delicate balance between available fresh water and a viable temperature range. Changes in the Sun's light/heat output which preceeded the massive explosion would have upset that delicate balance and turned the Earth into a cinder much like Venus and Mercury whose surface temperatures range to about 800 degrees F or more.

Remember that all this flap we are hearing now about Global Warming has to do with only a degree or two of increase in global temperatures. As a result, jumps of 50 to 100 degrees would turn paradise into a flaming hot desert. Seas, lakes and rivers would begin to dry up over night. Drought and famine would spread rather quickly. Massive forest fires would break out all over the globe. And, the human race would quickly die out, way before the supernova occurance.

Answer 4

Larry Niven once wrote a short story, "Inconstant Moon," that deals with this theme. A very interesting read, I might add.

The protagonist notices the moon grow very, very bright. (It is night on his side of the world). He begins to make preparations...

Although it would take light roughly 8 minutes, 20 seconds to reach us from the sun, the first we would know of it would be the instant flash vaporizing the dayside inhabitants of the earth. Imagine the light of the entire 400 billion stars of the galaxy pouring out of our sun. The shock wave would arrive moments after the light. Neutrinos would shine through the earth as though it were clear glass--of course, they do this already. But there would be enough radiation to shred the planet rather quickly. I doubt anyone, day or night side, would have much time for awareness of what was happening.

Answer 5

Something similar to what the citizens of Hiroshima saw. The Sun is too small a star to go nova. It will die with a wimper not a bang. Best candidate for a nearby super nova is Eta Carinae, it has an estimated mass 100 times the Sun's. I throws off about two solar masses of dust into its system each year. So if any intelligent life has surived its death throes they probably are enveloped in dust and can't see anything. Eta Carinae may have already gone nova. At 7,500 light years we won't know for a while when it does. Fortunately, we or our descendants, will be able to watch from a safe distance.

Answer 6

Probably the quickest death we could all imagine.

A supernova is the most violent event in the universe. A star going supernova emits as much light as a whole galaxy. Even without all the other radiation, that light alone would kill us if the sun went supernova.

This question is like what would an ant see when crawling towards a nuclear bomb that was just about to go off.

The answer is NOTHING.

Answer 7

It takes about 8 minutes for light from the sun to reach earth, so about eight minutes after the sun actually exploded, if you were very, very lucky, you might see the size of the sun go from a spot, to enveloping all visible parts of the sky. In that brief instant between when the sun began exploding, and when it's radiation became intense enough to vaporize the earth,( and or ignite the atmosphere), you would be vaporized. It would happen so fast, it's unlikely your brain would actually process what happened.

In other words, if the sun exploded, in a matter of seconds you'd heat up, turn to vapor, and be gone.

Answer 8

This is fairly accurate... although, It would take the light from the event about 8 minutes to reach us... the potential radiation would be close behind... and the shockwave(s) would follow quite a bit later to obliterate the planet

Although, as a sidenote, our sun is nowhere near large enough to ever go "supernova" and explode... it will most likely only become a red giant, expand several times its current size (past earth's orbit), destroy the planet and then eventually shrink down and become a white dwarf

Answer 9

The sun will never supernova because it does not have enough mass. It will most likely become a red giant in about 5 billion years.

Also, the light from the sun takes approximately 8 minutes to reach Earth.

Answer 10

actully in about 100,000,000,000 years it will explode by then the human race will be extict if it did we woudlnt see much of it cuz wed be dead in minutes the sun is 1AU (1 Astronical unit) away but it would still hit us if it did happen we would see a huge cloud of fire that is red yellow and orange after that when all the planets are disroud the left over peices of stars will form together and make a new soar system and a new sun and then people again they would have no clue we existed and i beleive that is probably what happened before us right now the sun doesnt have enough mass to explode but in a billion years it just might and then the end of us

Answer 11

The sun will never become a super nova.
If you could speed it up over a few billion years you would see it gradually expand into a red giant and engulf you.
If the sun could become a super nova,you would watch it grow rapidly from what it is until in eight minutes it would engulf you and the earth.