Archive for Hubble Space Telescope

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 Twelve Days of Johnny Mackintosh

Posted in Book news with tags , , , on December 2, 2009 by keithmansfield

Johnny Mackintosh: Star Blaze publishes on 7th January 2010. Traditionally, the twelve days of Christmas run through to January 6th, by which point the decorations have come down and it’s all well and truly over. Don’t despair. What more exciting thing to look forward to than a new book?

To get readers in the mood for the next instalment of Johnny and Clara’s adventures, I’ve created a series of twelve images that give the flavour running through the new story. Of course they won’t give anything away, but they’ll run sequentially through the new book, giving an idea of where my two heroes end up. I’ll be posting them, with an accompanying explanation, every day from Boxing Day through to 6th January. After you’ve unwrapped all your presents and eaten enough turkey that you’re fit to burst, make sure you drop in here on 26th December to witness the new story begin to unfold.

The image here gives you an indication of what to expect, but I’ve since replaced it with a better one. This superimposes one of my photos of the Spirit of London (some readers may think it’s the London Gherkin) against a Hubble Space Telescope star field.

Follow

Get every new post delivered to your Inbox.