In Search of the Cosmic Dawn
This past Friday, I attended the last of the Cosmic Frontiers series that celebrated the centennial of Astronomy at the University of Toronto. For this lecture, the organizers chose UofT's very own, Professor Bob Abraham. Abraham's lecture was titled, In Search of the Cosmic Dawn, and is summarized by the following abstract:
First impressions of Abraham was, "Whoa! This guy ain't that old!" He could easily be my age -- and when I think of the possibilities .... This is remarkable for me because I'm just trained to expect professors who've been around the block a few times, and have the long greying beard, not that much different from a wizard's, to show for it. Abraham was anything but. He was a pretty dynamic speaker, using humour quite a bit to keep his audience engaged. Not that most of us needed the humour -- but those with the attention span of a gnat may have needed it. Abraham's topic was interesting in its own right to keep me engaged and wanting more.
Abraham began by correcting what is apparently an incorrect quote of J. Robert Oppenheimer. According to Abraham, Oppenheimer didn't quote the Bhagavad Gita saying, "Now I am become Death, the Destroyer of worlds." What he said was "Now I am become Shiva, the Destroyer of worlds." The distinction is important for Abraham, because Einstein's famous energy-to-mass relationship that the bomb exploits isn't just a relationship about destruction -- it's also a relationship about creation. And Shiva, being part of the trimurti, doesn't exist without the creator, Brahma, and the preserver, Vishnu. This is important, because the rich universe we know today wouldn't have happened if not for the violent deaths of stars, which seeded gas clouds with elements heavier than helium -- which lead to new stars, planetary systems, and life on Earth. "We are star stuff."
The universe, three minutes after the Big Bang, was a very boring universe according to Abraham. It was filled with just hydrogen and helium -- and this state lasted for about one billion years -- an assertion that has been confirmed with the discovery of the cosmic microwave background radiation. The hydrogen and helium in that early universe is the same stuff we have here on Earth. In their gaseous state galaxies and stars can't be formed. Something miraculous happened however. At age 1 billion years old, the universe was bathed in what Abraham referred to as "first light." First light was an immense energy source that went through the entire universe and transformed the gaseous state of hydrogen and helium into plasma. In this state, hydrogen and helium, under the influence of gravity, could form the stars and galaxies that would be the birthplace of the Earth and life on it.
What is first light? That's the Nobel prize winning question. No one knows. We know it must have occurred 12.5 billion years ago, but so far our most powerful telescopes have not had the power to gaze that far back. Abraham suggested a few promising scenarios to discovering first light.
Abraham is quite excited about the possibility of finding first light before JWST is launched. He has however, placed his bets both with Gemini and JWST, as he participates in both programs. Whatever and whoever gets to first light first, what Abraham made clear is that there is a race going on. Hopefully there will be success soon.
As a side note, the pre-show for the lecture was mesmerizing. It featured galaxy dynamics simulations produced by John Dubinski. You can find some of those simulations here.
Our Universe was born in fantastic energy at the instant of the Big Bang, yet the first product of this moment of creation was a fairly drab Universe resembling a nearly featureless cloud of gas. This early Universe contained none of the richness and complexity that marks the present Cosmos: it was devoid of galaxies, devoid of stars, devoid of planets, devoid of even the basic chemistry that makes any of these things possible, and certainly devoid of life. This cosmic Dark Age was brought to an abrupt end by the onset of First Light, a sort-of cosmic Renaissance initiated by the formation of the first luminous objects in the Universe. The talk will describe how First Light led to the complex and rich Universe we see around us, through cycles of cosmic birth, death and rebirth, leading ultimately to intelligent life itself.
First impressions of Abraham was, "Whoa! This guy ain't that old!" He could easily be my age -- and when I think of the possibilities .... This is remarkable for me because I'm just trained to expect professors who've been around the block a few times, and have the long greying beard, not that much different from a wizard's, to show for it. Abraham was anything but. He was a pretty dynamic speaker, using humour quite a bit to keep his audience engaged. Not that most of us needed the humour -- but those with the attention span of a gnat may have needed it. Abraham's topic was interesting in its own right to keep me engaged and wanting more.
Abraham began by correcting what is apparently an incorrect quote of J. Robert Oppenheimer. According to Abraham, Oppenheimer didn't quote the Bhagavad Gita saying, "Now I am become Death, the Destroyer of worlds." What he said was "Now I am become Shiva, the Destroyer of worlds." The distinction is important for Abraham, because Einstein's famous energy-to-mass relationship that the bomb exploits isn't just a relationship about destruction -- it's also a relationship about creation. And Shiva, being part of the trimurti, doesn't exist without the creator, Brahma, and the preserver, Vishnu. This is important, because the rich universe we know today wouldn't have happened if not for the violent deaths of stars, which seeded gas clouds with elements heavier than helium -- which lead to new stars, planetary systems, and life on Earth. "We are star stuff."
The universe, three minutes after the Big Bang, was a very boring universe according to Abraham. It was filled with just hydrogen and helium -- and this state lasted for about one billion years -- an assertion that has been confirmed with the discovery of the cosmic microwave background radiation. The hydrogen and helium in that early universe is the same stuff we have here on Earth. In their gaseous state galaxies and stars can't be formed. Something miraculous happened however. At age 1 billion years old, the universe was bathed in what Abraham referred to as "first light." First light was an immense energy source that went through the entire universe and transformed the gaseous state of hydrogen and helium into plasma. In this state, hydrogen and helium, under the influence of gravity, could form the stars and galaxies that would be the birthplace of the Earth and life on it.
What is first light? That's the Nobel prize winning question. No one knows. We know it must have occurred 12.5 billion years ago, but so far our most powerful telescopes have not had the power to gaze that far back. Abraham suggested a few promising scenarios to discovering first light.
- Gamma ray bursts is one potential catalyst for first light. Gamma ray burst sources are all over the sky, and are thought to be a result of supermassive stars collapsing into black holes ... yet, if there weren't stars in the early universe ... yup, there's still work to be done.
- The James Webb Space Telescope, set to unfurl in space sometime in 2014, will be way, way bigger than Hubble and have the ability to peer further back into the past. JWST will be able to see back 12.5 billion years ago, and hopefully it will be able to see first light source(s).
- Going into space isn't the only option for peering that far back in time. The Gemini Telescope, already in operation, could be used in conjunction with adaptive optics and gravitational lenses to peer as far back as potentially 12.5 billion years ago. With just the right technology and the right observations, first light source(s) could be seen before JWST is launched.
Abraham is quite excited about the possibility of finding first light before JWST is launched. He has however, placed his bets both with Gemini and JWST, as he participates in both programs. Whatever and whoever gets to first light first, what Abraham made clear is that there is a race going on. Hopefully there will be success soon.
As a side note, the pre-show for the lecture was mesmerizing. It featured galaxy dynamics simulations produced by John Dubinski. You can find some of those simulations here.
Comments
Post a Comment