Echoes Of A Supernova
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The Hidden Universe (Episode 20): Cassiopeia A - Echoes of a Supernova A supernova flash echoing through surrounding dust clouds has given astronomers a virtual time machine for studying the light from the explosion that nobody saw.
This is the Hidden Universe of NASA's Spitzer Space Telescope, exploring the mysteries of infrared astronomy with your host Dr. Robert Hurt.
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It's the 17th century supernova that nobody saw, but telescopes in space and on Earth have teamed up to look back in time and study it today!
When a massive star reaches its end of days it explodes dramatically and, for a few months, can outshine anything else in the galaxy. Earlier supernovas had been seen by many, often shining brighter than the planets. Of course with no witnesses, and no records, it's difficult to tell exactly what kind of supernova it was.
A team led by astronomer Oliver Krause has, over the last few years, made a remarkable series of infrared observations of the region. These Spitzer Space Telescope images show shifting patterns of glowing dust beyond the remnant itself. These changes are so fast that they indicate motion at the speed of light!
To get what's happening we have to remember that light moves fast, but in such a vast galaxy it still takes a while for it to get anywhere. Cassiopeia A (Cas A) itself is about 11,000 light-years away, which means today we're seeing what it looked like 11,000 years ago. But that's only part of the story.
The light from a supernova can even take hundreds of years to reach surrounding dust clouds. Following the arrows of light it's clear we'll see the supernova flash first. The light echoing off of the dust clouds will later arrive at various times, delayed by hundreds of years from the original flash.
So we're not seeing the dust move, we're seeing the light from the supernova move through the dust. Out there, the flash is about as bright as the full moon, which is enough to warm the dust slightly. Spitzer detects this brief boost in its thermal infrared glow.
Now, knowing the location of the infrared light echo, Dr. Krause and his team went searching for a far more elusive visible-light echo. Using the powerful Subaru telescope in Hawaii they succeeded in measuring the very faint light of the supernova itself reflecting off the dust. The light echo has acted like an astronomical time machine, letting us study the original supernova using instruments that were beyond imagination in the 17th century.
By matching its visible spectral signature to a wellstudied supernova in a nearby galaxy, Krause and his team have now identified it as a so-called Type IIb supernova. A Type IIb is fainter than the earlier Type Ib supernovas noted by Tycho Brahe in 1572 and Johannes Kepler in 1604. Interestingly, the Royal Astronomer Flamsteed noted a star near Cas A in August of 1680 with a brightness consistent with a Type IIb supernova at that distance. So maybe it was seen after all!
But this light echo reveals more than just the supernova. The expanding flash also lets astronomers study the three-dimensional struct ure of the dust, illuminating it one slice at a time. If we combine the images, assigning colors to the observation dates, the result is a prismatic display of the 3D dust structure. The nearest dust is blue, and the most distant is red, while everything that stays constant is grey. We can see that interstellar dust lies in sheets and filaments, not, for instance, big, puffy clouds.
This remarkable light echo around Cas A has led to a better understanding of both supernovas and interstellar dust, which itself is made of elements forged in previous generations of supernovas. This also marks the start of the third year of our Hidden Universe podcasts. On behalf of the staff of the Spitzer Science Center, I'd like to thank all of our viewers for making this and our other podcasts so successful. And keep watching, because there's a lot more to this hidden universe just waiting to be discovered!
• http://www.spitzer.caltech.edu/
The Hidden Universe (Episode 20): Cassiopeia A - Echoes of a Supernova A supernova flash echoing through surrounding dust clouds has given astronomers a virtual time machine for studying the light from the explosion that nobody saw.
This is the Hidden Universe of NASA's Spitzer Space Telescope, exploring the mysteries of infrared astronomy with your host Dr. Robert Hurt.
---
Please subscribe to Science & Reason:
• http://www.youtube.com/Best0fScience
• http://www.youtube.com/ScienceMagazine
• http://www.youtube.com/ScienceTV
• http://www.youtube.com/FFreeThinker
---
It's the 17th century supernova that nobody saw, but telescopes in space and on Earth have teamed up to look back in time and study it today!
When a massive star reaches its end of days it explodes dramatically and, for a few months, can outshine anything else in the galaxy. Earlier supernovas had been seen by many, often shining brighter than the planets. Of course with no witnesses, and no records, it's difficult to tell exactly what kind of supernova it was.
A team led by astronomer Oliver Krause has, over the last few years, made a remarkable series of infrared observations of the region. These Spitzer Space Telescope images show shifting patterns of glowing dust beyond the remnant itself. These changes are so fast that they indicate motion at the speed of light!
To get what's happening we have to remember that light moves fast, but in such a vast galaxy it still takes a while for it to get anywhere. Cassiopeia A (Cas A) itself is about 11,000 light-years away, which means today we're seeing what it looked like 11,000 years ago. But that's only part of the story.
The light from a supernova can even take hundreds of years to reach surrounding dust clouds. Following the arrows of light it's clear we'll see the supernova flash first. The light echoing off of the dust clouds will later arrive at various times, delayed by hundreds of years from the original flash.
So we're not seeing the dust move, we're seeing the light from the supernova move through the dust. Out there, the flash is about as bright as the full moon, which is enough to warm the dust slightly. Spitzer detects this brief boost in its thermal infrared glow.
Now, knowing the location of the infrared light echo, Dr. Krause and his team went searching for a far more elusive visible-light echo. Using the powerful Subaru telescope in Hawaii they succeeded in measuring the very faint light of the supernova itself reflecting off the dust. The light echo has acted like an astronomical time machine, letting us study the original supernova using instruments that were beyond imagination in the 17th century.
By matching its visible spectral signature to a wellstudied supernova in a nearby galaxy, Krause and his team have now identified it as a so-called Type IIb supernova. A Type IIb is fainter than the earlier Type Ib supernovas noted by Tycho Brahe in 1572 and Johannes Kepler in 1604. Interestingly, the Royal Astronomer Flamsteed noted a star near Cas A in August of 1680 with a brightness consistent with a Type IIb supernova at that distance. So maybe it was seen after all!
But this light echo reveals more than just the supernova. The expanding flash also lets astronomers study the three-dimensional struct ure of the dust, illuminating it one slice at a time. If we combine the images, assigning colors to the observation dates, the result is a prismatic display of the 3D dust structure. The nearest dust is blue, and the most distant is red, while everything that stays constant is grey. We can see that interstellar dust lies in sheets and filaments, not, for instance, big, puffy clouds.
This remarkable light echo around Cas A has led to a better understanding of both supernovas and interstellar dust, which itself is made of elements forged in previous generations of supernovas. This also marks the start of the third year of our Hidden Universe podcasts. On behalf of the staff of the Spitzer Science Center, I'd like to thank all of our viewers for making this and our other podcasts so successful. And keep watching, because there's a lot more to this hidden universe just waiting to be discovered!
• http://www.spitzer.caltech.edu/
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science (especially medical research) is the reason that the population of our species is so out of control. such high populations are unsustainable and lead to poverty and extreme suffering. the more we've advanced in science, the more we've screwed up our planet and grown farther away from nature. nature never intended for one species to be so powerful and if any other species obtained as much power as us, we'd be the first to drop bombs on them.
I disagree first off you cant really say what nature has intended, has nature also intended massive stars to blow up in gigantic super novas and creating a black hole who is only a few kilometers diameter but with the same mass as the whole star and insane gravity that even light cant escape it? No, the laws are at work there, same it was with evolution, same it is with us now.
If a species has no natural predators that hunt them and they have more than enough food the species starts to increase in population rapidly, that has been observed.
For example your town is populated by sparrows, you destroy them, the insects population will rise rapidly. They have the food, your crop plantations, and no natural predator to decrease their population.
Science has helped man but theres more to it.
And whats your alternative?
Stop science, decrease population?
nature never for us to advance like this. we have disease for a reason, we have/had predators for a reason, we only lived to about half the age people are living today for a reason. now we've managed to evade these aspects of nature, see what has happened to the world. medical advancements may have helped individuals but such rocketing populations is why we have such povety in the world. earth's nature is a bunch of complex systems and processes to maintain life, whereas space is not.
What do you/we really know what nature has or has not intended? We do not. Have the laws of nature lead to such things as Black holes for a reason as well? The only reason we have diseases is because they are overall sucessful to survive, we still have predators, we didn't live half the age we live now for a reason, we lived half the age because the conditions rarely aloved some individuals to survive longer.
And you didn't answer my question: Whats your alternative?
you must be the only one that you don't know that a singular word can have more plural words =<