Archive for supernova

12. Star Blaze

Posted in 12 Days of Johnny Mackintosh, Science, Space, star blaze with tags , , , , , , , , on January 6, 2010 by keithmansfield

“Johnny knew … he had the best seat in the house to watch the greatest explosion in the history of the solar system.” p. 309

Credit: NASA/CXC/M.Weiss

First there was the big bang. By definition, nothing can match the initial outpouring of energy that we believe created the universe, but even today there are some pretty cataclysmic explosions. A supernova (the Star Blaze of the new book) happens when a large star reaches the end of its life. Stars fight a constant battle, the outward pressure from the nuclear reactions at their hearts counterbalancing the gravitational collapse due to all that matter being in one place. When the nuclear fuel runs out, there can be only one winner.

In that moment, the light from a single star outshines the rest of the galaxy that contains it. When you realize our own Milky Way contains at least 100 billion suns, we begin to understand just how bright and powerful a supernova really is. The image here is an artist’s vision of a supernova, based on Chandra X-Ray Telescope observations. Subramanian Chandrasekhar, who did more than anyone to enhance our understanding of stars and black holes, was one of the greatest scientists of last century. The telescope’s named after him, and I’m honoured that he called me his friend. At the start of Johnny Mackintosh: Star Blaze, I give the great man a name check.

It’s because of Chandra that we know our own Sun won’t, at some future stage, become a supernova, as its mass is less than the Chandrasekhar Limit. It’s also because of him that we know we can treat some supernovae as “standard candles”, which help us measure the scale of the universe. And it’s because of these yardsticks that we’ve recently discovered that the rate of expansion of the universe is speeding up rather than slowing down, accelerated by something called dark energy, the same force that powers the Spirit of London’s engines.

Although a supernova marks the death of a particular star, it’s part of the continual process of rebirth in the universe. None of us – not even Earth itself – could exist without the first stars exploding. We’re all made of different types of atoms, the basic elemental building blocks of the universe. The big bang only produced the two lightest elements, hydrogen and helium, with a minuscule amount of lithium (the next one up). All the other, heavier elements have had to be made since and the place they are created is in the heart of stars. Only when those stars die, becoming supernovae, can those atoms be spread across space and come together to form such things as people and planets. Carl Sagan first said, “We are all made of starstuff.”

Today marks the end of the Twelve Days of Johnny Mackintosh, but only because tomorrow sees a new birth.

5. Carina Nebula

Posted in 12 Days of Johnny Mackintosh, Science, Space, star blaze with tags , , , , , , , , on December 30, 2009 by keithmansfield

“move the First Fleet to the Keyhole Nebula . . . and the Third Fleet behind the great star Carinae itself”, p.70

Credit: NASA, Hubble Heritage Team (AURA/STScI)

For day five of Johnny Mackintosh, I’m giving you an amazing photo from the Hubble Space Telescope. My hope is that it shows the enigmatic star, Eta Carinae and the Keyhole Nebula, all embedded within the wider Carina Nebula. Sadly I’m forced to confess that, unlike Johnny, I haven’t seen it close to so am not quite sure what’s meant to be where! The Hubble Heritage Team has a separate labelled map that looks a little different, so you might try to superimpose one over the other.

The Ancient Greeks called the stars “fixed” (while the word planet means “wanderer”), but the heavens aren’t always as unchanging as they believed. Eta Carinae is classed as a hypergiant, about the biggest star there is – around a hundred times bigger than our own Sun. Its behaviour is unusual for how quickly it changes .

We should be grateful that astronomers have left meticulous records of their observations for hundreds of years. In 1677, Edmund Halley (who the comet is named after) classified Eta Carinae as “fourth magnitude”. Fifty years on, astronomers were surprised to record it as much brighter than this – perhaps Halley had made a mistake?

Yet, over the next fifty years, the star dimmed back down to where Halley had categorized it. Then, in the early 1840s, Eta Carina flared suddenly to become the second brightest star in the sky after Sirius, despite being a thousand times further away – scientists wondered if they were watching a supernova, the great explosion when a star tears itself apart. Yet the star remains in place. It quickly faded and by the start of the twentieth century had become invisible to the naked eye.

Late in 1997 Eta Carinae brightened again, so we can now see it without the aid of telescopes. There are only a very few stars in all the Milky Way of comparable size and there’s a rule – the bigger the star, the faster it burns its fuel. This means there’s a chance this giant is near the very end of its life, so we think it is one of the best candidates for a supernova in our galaxy in the near future.

Tomorrow we’re travelling back in time, to the early nineteenth century. It’s one of my favourite sections of the book.

The Second Johnny Mackintosh book

Posted in Book news, Space with tags , , , , on August 16, 2009 by keithmansfield

If you’ve come to this site because you’re desperate to discover more about the sequel to Johnny Mackintosh and the Spirit of London (and who could blame you), you’re in the right place. Finally, the full manuscript for Johnny Mackintosh: Star Blaze is with Quercus Books and in production, due to publish early in 2010.

Supernova image SN2006gyThe Star Blaze of the title is what we might normally call a supernova, the moment a star explodes at the end of its life. At that time, the light from a single sun will outshine the rest of its galaxy.

Of course it would be wrong to tell you what happens, but I have to say I’m very excited about the new book. I can say the action begins around five months after the end of Johnny Mackintosh and the Spirit of London and that you should check back soon as I’ll be posting a little taster…

[Image: artist’s impression of Supernova SN2007gy, courtesy NASA/CXC/M.Weiss; X-ray: NASA/CXC/UC Berkeley/N.Smith et al.; IR: Lick/UC Berkeley/J.Bloom & C.Hansen]

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