What is cosmos?
Saturday 25 May 2019
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Physics of the Cosmos
The Cosmos
Our quest to understand how the universe works starts with the study of the very basic building blocks of our existence - matter, energy, space, and time - and how they behave under the extreme physical conditions that characterize the infant and evolving Universe. The Physics of the Cosmos (PCOS) program incorporates cosmology, high-energy astrophysics, and fundamental physics projects aimed at addressing directly central questions about the nature of complex astrophysical phenomena such as black holes, neutron stars, dark energy, and gravitational waves. By utilizing a fleet of space-based missions operating across the whole electromagnetic spectrum, PCOS ultimate, overarching goal is to learn about the origin and ultimate destiny of the cosmos
About Us
Universe
Menu
PROGRAMS
Physics of the Cosmos
Cosmic Origins
Astrophysics Explorers
Exoplanet Exploration
Astrophysics Research
Astrophysics Div Technology
NASA Balloon Program
NASA Sounding Rockets
Cosmic Origins
In order to understand how the universe has changed from its initial simple state following the Big Bang into the magnificent universe we see as we look at the night sky, we must understand how stars, galaxies and planets are formed over time. The universe is comprised of mostly hydrogen and helium. in fact, these two elements make up 98% of the visible matter in the universe. Nevertheless, our world and everything it contains–even life itself–is possible only because of the existence of heavier elements such as carbon, nitrogen, oxygen, silicon, iron, and many, many others.
How long did it take the first generations of stars to seed our universe with the heavy elements we see on Earth today? When in the history of the universe was there a sufficient supply of heavy elements to allow the formation of prebiotic molecules and terrestrial-like planets upon which those molecules might combine to form life?
Our big question: "How did the universe originate and evolve to produce the galaxies, stars and planets we see today?"
About Us
Universe
Menu
PROGRAMS
Physics of the Cosmos
Cosmic Origins
Astrophysics Explorers
Exoplanet Exploration
Astrophysics Research
Astrophysics Div Technology
NASA Balloon Program
NASA Sounding Rockets
Astrophysics Explorers
Small- and medium-class, PI-led Astrophysics missions, as well as Astrophysics missions of opportunity, are selected under the Astrophysics Explorers program, and are managed by the Astrophysics Division. Explorers are opportunities for focused scientific investigations, and fill the scientific gaps between the larger missions. For example, the Nuclear Spectroscopic Telescope Array (NuSTAR) is conducting a census of black holes for the Physics of the Cosmos program and studying the birth of elements for the Cosmic Origins program. The Transiting Exoplanet Survey Satellite (TESS) is now in operations identifying terrestrial planets in the habitable zones of nearby stars. The Neutron Star Interior Composition Explorer (NICER) mission of opportunity has been mounted on the space station and is measuring the variability of cosmic X-ray sources to explore the exotic states of matter within neutron stars and reveal their interior and surface compositions.
Several future missions are in development. The Imaging X-Ray Polarimetry Explore (IXPE) will use the polarization state of light from astrophysical sources to provide insight into our understanding of X-ray production in objects such as neutron stars and pulsar wind nebulae, as well as stellar and supermassive black holes. Mission of Opportunity GUSTO (Galactic/extragalactic Ultra long duration balloon Spectroscopic Terahertz Observatory) will untangle the complexities of the interstellar medium and map out large sections of the plane of our Milky Way galaxy and the nearby galaxy known as the Large Magellanic Cloud. Finally, XRISM (X-Ray Imaging and Spectroscopy, previously named XARM) is a JAXA/NASA collaborative mission with ESA participation which will investigate X-ray celestial objects in the Universe with high-throughput, high-resolution spectroscopy.
Cosmology has been radically transformed in the past few decades. The study of the origins of the Universe once entailed plenty of speculation and few data. Now, an impressive array of ground- and space-based telescopes produce vast amounts of data, and the 'standard' cosmological theory fits it exquisitely and in detail. The subject of Zeeya Merali's
A Big Bang in a Little Room
— the possibility of creating a universe in a laboratory — ties in very broadly with these exciting developments.
The Large Hadron Collider, one of the few facilities that can recreate conditions of the early Universe.
Image: James King-Holmes/SPL
The astronomical data show that the Universe gets hotter as we go further back in time. These conditions can be recreated only with great effort at laboratories with particle accelerators, such as CERN in Europe and Fermilab in the United States. High-energy physics has introduced interesting possibilities and insights — such as the idea that the very early Universe underwent an accelerated expansion, or cosmic inflation, and the possibility that the observed Universe was produced by a quantum-tunnelling event (perhaps tunnelling out of a lab). Among these developments, Merali shows, there are great stories and colourful characters.
Merali, an accomplished science writer, weaves a picture of modern cosmology from its results, its history and the motivations of individuals. Thoughts from Alan Guth, Andrei Linde and Alex Vilenkin about the development of cosmic inflation, and from Joe Polchinski about the evolution of string theory (to mention a few), wonderfully convey the sometimes thrilling and often circuitous nature of scientific progress, and its emotional ups and downs. Many of the scientists profiled are colleagues of whom I am fond, and it is gratifying to see their wisdom and quirks shine in Merali's excellent prose.
Each chapter focuses on one key subtopic, and features scientists who work in it. We learn about the foundations of quantum physics through the reflections of Antoine Suarez on his distinguished career creating ever more powerful laboratory tests of quantum theory. Greg Landsberg shares his expertise on the search for mini black holes at CERN, and Eduardo Guendelman describes his pioneering work on how they could be the seeds of baby universes. Other chapters take on determinism and free will, and the ethics of creating artificial life.
The question of cosmic origins, and the possibility that humans might create new universes, can connect with religious concerns. These form a substantial thread through
A Big Bang in a Little Room
that significantly reduced the book's appeal to me. I am an atheist. I respect that many people are deeply religious (some are very close to me) and that religion can have a positive, even beautiful, role. And I know many religious people who do superb science. But I find most attempts to connect religious questions with the fundamental questions of physics and cosmology (or vice versa) deeply unsatisfying.
Does your favourite interpretation of quantum mechanics or apparent fine-tuning of the fundamental constants provide evidence for or against a divine creator? Deeply religious people know better than to leave something so important to them to fads in physics. And when people do engage in these debates, they seem to find a reason to believe what they want to believe, regardless of how the science unfolds.
For example, Suarez shares how his religious convictions (about determinism and divine omniscience) convinced him that his experiments would disprove quantum theory. But once his experiments had upheld the theory, he found a new way to fit a deity into the picture, by identifying the “many worlds” proposed by US physicist Hugh Everett with thoughts in the “mind of God”.
The diversity of scientists' religious beliefs is an interesting topic, and there is some good writing on it throughout
A Big Bang in a Little Room
. Merali is not shy about airing her own religious views, and they clearly inform her enthusiasm for talking to scientists about theirs. Some of her interviewees share thoughtful contemplations; Guendelman ponders why an all-powerful god would allow horrifying evil. But weaker discussions let the book down, including a lengthy exploration (bringing in Polchinski and Christoph Schönborn, the archbishop of Vienna) of whether string theory supports or refutes the existence of god. And, given how central religion is to this book, it seems strange that neither the title nor the blurb mentions it.
Atheist readers more uncompromising than me may find this book unbearable. Even deeply religious readers may not welcome the sloppy interplay between science and religion. Still, there are those who enjoy debating perceived relationships between this or that physics concept and the existence of a god: it is probably they who will enjoy the book most fully.
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