Why Is There Something Rather Than Nothing

By Robert Adler
6 November 2014
Original source:  http://www.bbc.com/earth/story/20141106-why-does-anything-exist-at-all

People have wrestled with the mystery of why the universe exists for thousands of years. Pretty much every ancient culture came up with its own creation story - most of them leaving the matter in the hands of the gods - and philosophers have written reams on the subject. But science has had little to say about this ultimate question.

However, in recent years a few physicists and cosmologists have started to tackle it. They point out that we now have an understanding of the history of the universe, and of the physical laws that describe how it works. That information, they say, should give us a clue about how and why the cosmos exists.

Their admittedly controversial answer is that the entire universe, from the fireball of the Big Bang to the star-studded cosmos we now inhabit, popped into existence from nothing at all. It had to happen, they say, because "nothing" is inherently unstable.

This idea may sound bizarre, or just another fanciful creation story. But the physicists argue that it follows naturally from science's two most powerful and successful theories: quantum mechanics and general relativity.

Here, then, is how everything could have come from nothing.

(Credit: NASA, ESA, M. Postman (STScI), CLASH Team, Hubble Heritage Team (STScI/AURA))

Particles from empty space

First we have to take a look at the realm of quantum mechanics. This is the branch of physics that deals with very small things: atoms and even tinier particles. It is an immensely successful theory, and it underpins most modern electronic gadgets.

Quantum mechanics tells us that there is no such thing as empty space. Even the most perfect vacuum is actually filled by a roiling cloud of particles and antiparticles, which flare into existence and almost instantaneously fade back into nothingness.

These so-called virtual particles don't last long enough to be observed directly, but we know they exist by their effects.

The Stephan's Quintet group of galaxies (Credit: NASA, ESA, and the Hubble SM4 ERO Team)

Space-time, from no space and no time

From tiny things like atoms, to really big things like galaxies. Our best theory for describing such large-scale structures is general relativity, Albert Einstein's crowning achievement, which sets out how space, time and gravity work.

Relativity is very different from quantum mechanics, and so far nobody has been able to combine the two seamlessly. However, some theorists have been able to bring the two theories to bear on particular problems by using carefully chosen approximations. For instance, this approach was used by Stephen Hawking at the University of Cambridge to describe black holes.

    In quantum physics, if something is not forbidden, it necessarily happens

One thing they have found is that, when quantum theory is applied to space at the smallest possible scale, space itself becomes unstable. Rather than remaining perfectly smooth and continuous, space and time destabilize, churning and frothing into a foam of space-time bubbles.

In other words, little bubbles of space and time can form spontaneously. "If space and time are quantized, they can fluctuate," says Lawrence Krauss at Arizona State University in Tempe. "So you can create virtual space-times just as you can create virtual particles."

What's more, if it's possible for these bubbles to form, you can guarantee that they will. "In quantum physics, if something is not forbidden, it necessarily happens with some non-zero probability," says Alexander Vilenkin of Tufts University in Boston, Massachusetts.

Maybe it all began with bubbles (Credit: amira_a, CC by 2.0)

A universe from a bubble

So it's not just particles and antiparticles that can snap in and out of nothingness: bubbles of space-time can do the same. Still, it seems like a big leap from an infinitesimal space-time bubble to a massive universe that hosts 100 billion galaxies. Surely, even if a bubble formed, it would be doomed to disappear again in the blink of an eye?

    If all the galaxies are flying apart, they must once have been close together

Actually, it is possible for the bubble to survive. But for that we need another trick: cosmic inflation.


Most physicists now think that the universe began with the Big Bang. At first all the matter and energy in the universe was crammed together in one unimaginably small dot, and this exploded. This follows from the discovery, in the early 20th century, that the universe is expanding. If all the galaxies are flying apart, they must once have been close together.

Inflation theory proposes that in the immediate aftermath of the Big Bang, the universe expanded much faster than it did later. This seemingly outlandish notion was put forward in the 1980s by Alan Guth at the Massachusetts Institute of Technology, and refined by Andrei Linde, now at Stanford University.

    As weird as it seems, inflation fits the facts

The idea is that, a fraction of a second after the Big Bang, the quantum-sized bubble of space expanded stupendously fast. In an incredibly brief moment, it went from being smaller than the nucleus of an atom to the size of a grain of sand. When the expansion finally slowed, the force field that had powered it was transformed into the matter and energy that fill the universe today. Guth calls inflation "the ultimate free lunch".

As weird as it seems, inflation fits the facts rather well. In particular, it neatly explains why the cosmic microwave background, the faint remnant of radiation left over from the Big Bang, is almost perfectly uniform across the sky. If the universe had not expanded so rapidly, we would expect the radiation to be patchier than it is.

The cosmic microwave background
(Credit: NASA / WMAP Science Team)

The universe is flat and why that's important

Inflation also gave cosmologists the measuring tool they needed to determine the underlying geometry of the universe. It turns out this is also crucial for understanding how the cosmos came from nothing.

Einstein's theory of general relativity tells us that the space-time we live in could take three different forms. It could be as flat as a table top. It could curve back on itself like the surface of a sphere, in which case if you travel far enough in the same direction you would end up back where you started. Alternatively, space-time could curve outward like a saddle. So which is it?

There is a way to tell. You might remember from maths class that the three angles of a triangle add up to exactly 180 degrees. Actually your teachers left out a crucial point: this is only true on a flat surface. If you draw a triangle on the surface of a balloon, its three angles will add up to more than 180 degrees. Alternatively, if you draw a triangle on a surface that curves outward like a saddle, its angles will add up to less than 180 degrees.

So to find out if the universe is flat, we need to measure the angles of a really big triangle. That's where inflation comes in. It determined the average size of the warmer and cooler patches in the cosmic microwave background. Those patches were measured in 2003, and that gave astronomers a selection of triangles. As a result, we know that on the largest observable scale our universe is flat.

(Credit: It may not look flat... (Credit: NASA, ESA, and The Hubble Heritage Team (AURA/STScI))

It turns out that a flat universe is crucial. That's because only a flat universe is likely to have come from nothing.

Everything that exists, from stars and galaxies to the light we see them by, must have sprung from somewhere. We already know that particles spring into existence at the quantum level, so we might expect the universe to contain a few odds and ends. But it takes a huge amount of energy to make all those stars and planets.

    The energy of matter is exactly balanced by the energy of the gravity the mass creates

Where did the universe get all this energy? Bizarrely, it may not have had to get any. That's because every object in the universe creates gravity, pulling other objects toward it. This balances the energy needed to create the matter in the first place.

It's a bit like an old-fashioned measuring scale. You can put a heavy weight on one side, so long as it is balanced by an equal weight on the other. In the case of the universe, the matter goes on one side of the scale, and has to be balanced by gravity.

Physicists have calculated that in a flat universe the energy of matter is exactly balanced by the energy of the gravity the mass creates. But this is only true in a flat universe. If the universe had been curved, the two sums would not cancel out.

Matter on one side, gravity on the other (Credit: Da Sal, CC by 2.0)

Universe or multiverse?

At this point, making a universe looks almost easy. Quantum mechanics tells us that "nothing" is inherently unstable, so the initial leap from nothing to something may have been inevitable. Then the resulting tiny bubble of space-time could have burgeoned into a massive, busy universe, thanks to inflation. As Krauss puts it, "The laws of physics as we understand them make it eminently plausible that our universe arose from nothing - no space, no time, no particles, nothing that we now know of."

So why did it only happen once? If one space-time bubble popped into existence and inflated to form our universe, what kept other bubbles from doing the same?

    There could be a mind-boggling smorgasbord of universes

Linde offers a simple but mind-bending answer. He thinks universes have always been springing into existence, and that this process will continue forever.

When a new universe stops inflating, says Linde, it is still surrounded by space that is continuing to inflate. That inflating space can spawn more universes, with yet more inflating space around them. So once inflation starts it should make an endless cascade of universes, which Linde calls eternal inflation. Our universe may be just one grain of sand on an endless beach.

Those universes might be profoundly different to ours. The universe next door might have five dimensions of space rather than the three – length, breadth and height – that ours does. Gravity might be ten times stronger or a thousand times weaker, or not exist at all. Matter might be built out of utterly different particles.

So there could be a mind-boggling smorgasbord of universes. Linde says eternal inflation is not just the ultimate free lunch: it is the only one at which all possible dishes are available.

As yet we don't have hard evidence that other universes exist. But either way, these ideas give a whole new meaning to the phrase "Thanks for nothing".

Lawrence M. Krauss

From Wikipedia, the free encyclopedia

Lawrence M. Krauss
Krauss at Ghent University, October 17, 2013
Born	Lawrence Maxwell Krauss (1954-05-27) May 27, 1954 (age 61) New York, New York, USA
Nationality	American
Fields	Theoretical physics Cosmology
Institutions	Arizona State University Australian National University New College of the Humanities Yale University Case Western Reserve University Harvard University
Alma mater	Massachusetts Institute of Technology (PhD) Carleton University (BSc)
Thesis	Gravitation and phase transitions in the early universe (1982)
Doctoral advisor	Roscoe Giles[1]
Known for	Dark energy Zero-energy modeling
Notable awards	Andrew Gemant Award (2001) Lilienfeld Prize (2001) Science Writing Award (2002) Oersted Medal (2004)
Spouse	Katherine Kelley (1980–2012; divorced, 1 child) Nancy Dahl (2014–present)
Website krauss.faculty.asu.edu

Lawrence Maxwell Krauss (born May 27, 1954) is an American theoretical physicist and cosmologist who is Foundation Professor of the School of Earth and Space Exploration at Arizona State University and director of its Origins Project.^[2] He is known as an advocate of the public understanding of science, of public policy based on sound empirical data, of scientific skepticism and of science education and works to reduce the impact of what he opines as superstition and religious dogma in pop culture.^[3] Krauss is also the author of several bestselling books, including The Physics of Star Trek and A Universe from Nothing, and chairs the Bulletin of the Atomic Scientists Board of Sponsors.^[4]

Biography

Early life and education

Krauss was born in New York City, but spent his childhood in Toronto, Ontario, Canada.^[5] Krauss received undergraduate degrees in mathematics and physics with first class honours at Carleton University (Ottawa) in 1977, and was awarded a Ph.D. in physics at the Massachusetts Institute of Technology in 1982.^[6][7]

Personal life

On January 19, 1980, he married Katherine Kelley, a native of Nova Scotia. Their daughter, Lilli was born November 23, 1984. Krauss and Kelley separated in 2010 and were divorced in 2012. Krauss married Australian/American Nancy Dahl on January 7, 2014, and spends some of the Arizona summer in Australia at the Mount Stromlo Observatory.^[8][9]

Career

After some time in the Harvard Society of Fellows, Krauss became an assistant professor at Yale University in 1985 and associate professor in 1988. He was named the Ambrose Swasey Professor of Physics, professor of astronomy, and was chairman of the physics department at Case Western Reserve University from 1993 to 2005. In 2006, Krauss led the initiative for the no-confidence vote against Case Western Reserve University's president Edward M. Hundert and provost Anderson by the College of Arts and Sciences faculty. On March 2, 2006, both no-confidence votes were carried: 131–44 against Hundert and 97–68 against Anderson.

In August 2008, Krauss joined the faculty at Arizona State University as a Foundation Professor in the School of Earth and Space Exploration at the Department of Physics in the College of Liberal Arts and Sciences. He also became the Director of the Origins Project, a university initiative.^[10] In 2009, he helped inaugurate this initiative at the Origins Symposium, in which eighty scientists participated and three thousand people attended.^[11]

Krauss appears in the media both at home and abroad to facilitate public outreach in science. He has also written editorials for The New York Times. As a result of his appearance in 2004 before the state school board of Ohio, his opposition to intelligent design has gained national prominence.^[12]

Krauss attended and was a speaker at the Beyond Belief symposia in November 2006 and October 2008. He served on the science policy committee for Barack Obama's first (2008) presidential campaign and, also in 2008, was named co-president of the board of sponsors of the Bulletin of the Atomic Scientists. In 2010, he was elected to the board of directors of the Federation of American Scientists, and in June 2011, he joined the professoriate of the New College of the Humanities, a private college in London.^[13] In 2013, he accepted a part-time professorship at the Research School of Astronomy and Astrophysics in the Physics Department of the Australian National University.^[9]

Krauss is a critic of string theory, which he discusses in his 2005 book Hiding in the Mirror.^[14] Another book, released in March 2011, was titled Quantum Man: Richard Feynman's Life in Science, while A Universe from Nothing —with an afterword by Richard Dawkins—was released in January 2012 and became a New York Times bestseller within a week. Originally, its foreword was to have been written by Christopher Hitchens, but Hitchens grew too ill to complete it.^[15][16] The paperback version of the book appeared in January 2013 with a new question-and-answer section and a preface integrating the 2012 discovery of the Higgs boson at the LHC.

A July 2012 article in Newsweek, written by Krauss, indicates how the Higgs particle is related to our understanding of the Big Bang. He also wrote a longer piece in the New York Times explaining the science behind and significance of the particle.^[17]

Scientific work

Krauss lecturing about cosmology at TAM 2012

Krauss mostly works in theoretical physics and has published research on a great variety of topics within that field. His primary contribution is to cosmology as one of the first physicists to suggest that most of the mass and energy of the universe resides in empty space, an idea now widely known as "dark energy". Furthermore, Krauss has formulated a model in which the universe could have potentially come from "nothing," as outlined in his 2012 book A Universe from Nothing. He explains that certain arrangements of relativistic quantum fields might explain the existence of the universe as we know it while disclaiming that he "has no idea if the notion [of taking quantum mechanics for granted] can be usefully dispensed with".^[18] As his model appears to agree with experimental observations of the universe (such as of its shape and energy density), it is referred to as a "plausible hypothesis".^[19][20]

Initially, Krauss was skeptical of the Higgs mechanism. However, after the existence of the Higgs boson was confirmed by CERN, he has been researching the implications of the Higgs field on the nature of dark energy.^[21]

Atheist activism

Krauss describes himself as an antitheist^[22] and takes part in public debates on religion. Krauss featured in the 2013 documentary The Unbelievers, in which he and Richard Dawkins travel across the globe speaking publicly about the importance of science and reason as opposed to religion and superstition. The documentary also contains short clips of prominent figures such as Ayaan Hirsi Ali, Cameron Diaz, Sam Harris, and Stephen Hawking.^[23]

In his book, A Universe from Nothing: Why There is Something Rather than Nothing (2012), Krauss discusses the premise that something cannot come from nothing, which has often been used as an argument for the existence of a Prime mover. He has since argued in a debate with John Ellis and Don Cupitt that the laws of physics allow for the universe to be created from nothing. "What would be the characteristics of a universe that was created from nothing, just with the laws of physics and without any supernatural shenanigans? The characteristics of the universe would be precisely those of the ones we live in." ^[24] In an interview with The Atlantic, however, he states that he has never claimed that "questions about origins are over." According to Krauss, "I don't ever claim to resolve that infinite regress of why-why-why-why-why; as far as I'm concerned it's turtles all the way down."^[25]

Krauss has participated in many debates with theologians and apologists, including William Lane Craig and Hamza Tzortzis.^[26] The debate with Tzortzis resulted in controversy when Krauss complained to the iERA organisers about the gender segregation of the audience; he only stayed when men and women were allowed to sit together.^[27] Later, in discussions around secular liberal democracies and homosexuality, Krauss was asked "Why is incest wrong?" and answered that "Generally incest produces genetic defects" leading to "an ingrained incest taboo in almost all societies" though it could be theoretically permissible under rare circumstances where contraception is used.^[28][29]

Honors

Krauss is one of the few living physicists described by Scientific American as a "public intellectual"^[20] and he is the only physicist to have received awards from all three major American physics societies: the American Physical Society, the American Association of Physics Teachers, and the American Institute of Physics. In 2012, he was awarded the National Science Board's Public Service Medal for his contributions to public education in science and engineering in the United States.^[30]

During December 2011, Krauss was named as a non-voting honorary board member for the Center for Inquiry.^[31]

Bibliography

Krauss has authored or co-authored more than three hundred scientific studies and review articles on cosmology and theoretical physics.

Books

• Krauss, Lawrence M. (1989). The Fifth Essence. Basic Books. ISBN 978-0465023752. 
• Fear of Physics: A Guide for the Perplexed (1994), Basic Books, ISBN 0-465-02367-3
• The Physics of Star Trek (1996), Basic Books, ISBN 0-465-00559-4
• Beyond Star Trek: Physics from Alien Invasions to the End of Time (1998), Harper Collins, ISBN 978-0060977573
• Quintessence: The Search for Missing Mass in the Universe (2000), Basic Books, ISBN 0-465-03741-0
• Atom: An Odyssey from the Big Bang to Life on Earth...and Beyond (2002), Black Bay, ISBN 0-316-18309-1
• Hiding in the Mirror: The Mysterious Allure of Extra Dimensions, from Plato to String Theory and Beyond (2005), Viking, ISBN 0-670-03395-2
• Quantum Man: Richard Feynman's Life in Science (2011), Norton and Co. ISBN 978-0-393-06471-1
• A Universe from Nothing: Why There Is Something Rather Than Nothing (2012), Atria Books, ISBN 978-1-4516-2445-8 ^[32]

Contributor

• 100 Things to Do Before You Die (plus a few to do afterwards). 2004. Profile Books.
• The Religion and Science Debate: Why Does It Continue? 2009. Yale Press.

Articles

• THE ENERGY OF EMPTY SPACE THAT ISN'T ZERO. 2006. Edge.org ^[33]
• A dark future for cosmology. 2007. Physics World.
• The End of Cosmology. 2008. Scientific American.
• The return of a static universe and the end of cosmology. 2008. International journal of modern physics.
• Late time behavior of false vacuum decay: Possible implications for cosmology and metastable inflating states. 2008. Physical Review Letters.
• Krauss, Lawrence M. (June 2010). "Why I love neutrinos". Scientific American 302 (6): 19. doi:10.1038/scientificamerican0610-34. 

Media

Documentary films

• The Unbelievers (2013)
• The Principle (2014)

Television

• How the Universe Works (2010–)

Films

• London Fields (2015) (cameo)^[34]
• Salt and Fire (2016)

Awards

Krauss (right) during TAM9 in 2011, with Neil DeGrasse Tyson and Pamela Gay.

• Gravity Research Foundation First Prize Award in the 1984 Essay Competition^[35]
• Presidential Investigator Award (1986)^{[citation needed]}
• American Association for the Advancement of Science's Award for the Public Understanding of Science and Technology (2000)^[36]
• Julius Edgar Lilienfeld Prize (2001)^[37]
• Andrew Gemant Award (2001)^[38]
• American Institute of Physics Science Writing Award (2002)^[39]
• Oersted Medal (2003)^[40]
• American Physical Society Joseph P. Burton Forum Award (2005)^[41]
• Center for Inquiry World Congress Science in the Public Interest Award (2009)^[42]
• Helen Sawyer Hogg Prize of the Royal Astronomical Society of Canada and the Astronomical Society of Canada (2009)^[10]
• Physics World Book of the Year 2011 for Quantum Man^[43]
• National Science Board 2012 Public Service Award and Medal (2012)^[44]
• Premio Roma "Urbs Universalis", Rome (2013)^[45]
• Elected as Laureate of the International Academy of Humanism (2013)^[46]
• AFO (Academia Film Olomouc) Award for Outstanding Personal Contribution to the Popularization of Science, 49th Annual AFO Festival April 19, 2014. Olomouc, Czech Republic ^[47]
• Gravity Research Foundation First Prize Award in the 2014 Essay Competition^[48]
• Humanist of the Year, 2015, American Humanist Association^[49]