Watch that star – it may explode!

Eta Carinae Nebula image by Gerry Aarts

Keyhole Nebula, image Gerry Aarts

The dark Keyhole Nebula, visible in the picture above by the president of the Western Sydney Amateur Astronomical Group, Gerry Aarts,is part of the Eta Carinae Nebula. If you are at a dark spot in the country away from lights, you can see this nebula with your naked eye as a bright knot in the Milky Way, not far from the Southern Cross.

Also visible in Gerry’s picture is a bright star to the right of centre. That it the star Eta Carinae itself. Situated about 8000 light years from our Sun, it is a massive star that is at least 100 times more massive than the Sun.

Eta Carinae imaged by the Hubble space Telescope

Eta Carinae surrounded by dust lobes, imaged by the Hubble Space Telescope. Courtesy Credit: Jon Morse (University of Colorado), and NASA

In the 1840s Eta Carinae brightened and became the second brightest star in the sky. During that period it ejected two dust lobes that are slowly expanding away from the star. These can be easily seen in the famous Hubble Space Telescope image above.

Astronomers think that Eta Carinae is highly unstable and may become explode as a supernova at any time. Of course, as light from the star takes 8000 years to reach us, that may have already happened!

10 responses to “Watch that star – it may explode!

  • Thanks Susan. When it does explode it will look like a bright pinpoint of light in the sky visible by day and night. It maybe so bright that it will be dangerous to look at it directly as it may damage people’s eyesight. Note that astronomers think in terms of long time scales. So when I or another astronomer says that it may explode any time they mean that it may explode any time in the next 20,000 years or so. The star may go supernova in our life time or that of our great great great ….. grandchildren.

  • Thank you Mr Lomb, I do not question the integrity of scientists as a whole community of people trying to discover new ways of proggressing our existence, but i have heard from some scientists i know, conflicting opinions! that’s all, and i am not so satisfied as the average joe on such matters, where answers are concerned. it is exiting i guess because some people consider eta carinae to possibly be “God”? who knows lol…but for now i shall believe you because you seem so very kind.
    thank you.

    so what will it look like in our sky then? when it explodes? and how big during daylight should it probably be? i hope to see it i am all excited now!.

  • Hello Susan. There are more important things to worry about than distant exploding stars. Scientists may disagree in their results on complex questions, but they do not censor their results to pander to people’s feelings. According to NASA and Kansas University (http://www.spacedaily.com/news/supernova-03b.html) a supernova would have to be as close as 26 light years to cause significant damage to the ozone layer and to flood the surface with dangerous ultra-violet radiation. Eta Carinae is about 300 times further away so the intensity of radiation from it, which goes as the square of the distance, is about 10 000 times less – too little to cause damage.

  • I am reading so much conflicting imformation about the damage eta could or could not do!, and speculations about the light years distance..
    I am worried that this star might have a very detrimental effect on us here, if so then how long have we got before the actual effects reached our space and what would it do apart form depleting ozone and will we suffer? i feel that we are being given a syrup version so as not to scare us and i like proper facts.
    Thank you.

  • The Eta Car nova is also tilted away from the Earth, so even if it did explode, along with it being farther away than 26 light years, it wont hurt us, but you could see it exploding in the night sky tho when it does…

  • How likely is it that satellites or astronauts in space would be harmed by eta car’s explosion? My 7 year old son is very interested and I thank you for any information you might have.
    Please don’t use our last name.

  • Naomi, a supernova is a star that explodes. While it is exploding and for a short time afterwards it puts out as much as light and enery as an entire galaxy.

    As explained in answer to the previous comment above, supernovae can be dangerous, but only if we were unlucky enough to be very close to one. They should be regarded instead as beneficial for they put reprocessed material from the interiors of stars back into space. This material then forms new generations of stars and planets. Much of the materials in our bodies such as carbon and oxygen were formed inside stars and then scattered into space by long ago supernova explosions.

  • You are right Kenneth. A nearby supernova could do major damage to the ozone layer. The mechanism is that cosmic rays and gamma rays, which are highly energetic photons or particles of light, hit nitrogen atoms in the atmosphere and through a series of interactions create nitrogen oxides. These oxides than react and destroy the ozone molecules. The destruction of the ozone layer would allow ultraviolet light to reach the ground and lead to the mass extinctions.

    Recent calculations indicate that for serious damage to the ozone layer to occur the supernova has to be within 26 light years from Earth. Fortunately, Eta Carinae is about 8000 light years away so this time we are safe. Mass extictions from supernova may have happened in the early days of Earth’s history.

    More details at http://www.nasa.gov/centers/goddard/news/topstory/2003/0108supernova.html.

  • I have heard that a “near by” super nova can damage the earth”s ozone layer. Is this true and if so is Eta Carinae close enough to do this? Has this ever happened to earth in the past?

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