from the world's big
Can a Universe Create Itself Out of Nothing?
How can an entire universe come out of nothing? This would seem to violate the conservation of matter and energy, but Michio Kaku explains the answer.
Every Wednesday, Michio Kaku will be answering reader questions about physics and futuristic science. If you have a question for Dr. Kaku, just post it in the comments section below and check back on Wednesdays to see if he answers it.
Today, Dr. Kaku addresses a question posed by Brian Flatt.
"In Stephen Hawking’s new book The Grand Design, he says that because of the law of gravity, the universe can and will create itself out of nothing. But I thought that gravity was a function of mass, as per Einstein. How can you have gravity before mass and therefore how can gravity explain mass?"
Dr. Kaku: In Stephen's new book, he says that the Theory of Everything that Einstein spent 30 years of his life chasing is string theory (or its latest incarnation, M-theory).
In string theory, we have a multiverse of universes. Think of our universe as the surface of a soap bubble, which is expanding. We live on the skin of this bubble. But string theory predicts that there should be other bubbles out there, which can collide with other bubbles or even sprout or bud baby bubbles, as in a bubble bath.
But how can an entire universe come out of nothing? This apparently violates the conservation of matter and energy. But there is a simple answer.
Matter, of course, has positive energy. But gravity has negative energy. (For example, you have to add energy to the earth in order to tear it away from the sun. One separated far from the solar system, the earth then has zero gravitational energy. But this means that the original solar system had negative energy.)
If you do the math, you find out that the sum total of matter in the universe can cancel against the sum total of negative gravitational energy, yielding a universe with zero (or close to zero) net matter/energy. So, in some sense, universes are for free. It does not take net matter and energy to create entire universes. In this way, in the bubble bath, bubbles can collide, create baby bubbles, or simple pop into existence from nothing.
This gives us a startling picture of the big bang, that our universe was born perhaps from the collision of two universes (the big splat theory), or sprouted from a parent universe, or simply popped into existence out of nothing. So universes are being created all the time. (But Hawking goes one step farther and says that therefore here is no need of God, since God is not necessary to create the universe. I wouldn't go that far. See a previous blog entry on my attitude towards that.)
Ever since we've had the technology, we've looked to the stars in search of alien life. It's assumed that we're looking because we want to find other life in the universe, but what if we're looking to make sure there isn't any?
Here's an equation, and a rather distressing one at that: N = R* × fP × ne × f1 × fi × fc × L. It's the Drake equation, and it describes the number of alien civilizations in our galaxy with whom we might be able to communicate. Its terms correspond to values such as the fraction of stars with planets, the fraction of planets on which life could emerge, the fraction of planets that can support intelligent life, and so on. Using conservative estimates, the minimum result of this equation is 20. There ought to be 20 intelligent alien civilizations in the Milky Way that we can contact and who can contact us. But there aren't any.
Frequent shopping for single items adds to our carbon footprint.
- A new study shows e-commerce sites like Amazon leave larger greenhouse gas footprints than retail stores.
- Ordering online from retail stores has an even smaller footprint than going to the store yourself.
- Greening efforts by major e-commerce sites won't curb wasteful consumer habits. Consolidating online orders can make a difference.
A pile of recycled cardboard sits on the ground at Recology's Recycle Central on January 4, 2018 in San Francisco, California.
Photo by Justin Sullivan/Getty Images<p>A large part of the reason is speed. In a competitive market, pure players use the equation, <em>speed + convenience</em>, to drive adoption. This is especially relevant to the "last mile" GHG footprint: the distance between the distribution center and the consumer.</p><p>Interestingly, the smallest GHG footprint occurs when you order directly from a physical store—even smaller than going there yourself. Pure players, such as Amazon, are the greatest offenders. Variables like geographic location matter; the team looked at shopping in the UK, the US, China, and the Netherlands. </p><p>Sadegh Shahmohammadi, a PhD student at the Netherlands' Radboud University and corresponding author of the paper, <a href="https://www.cnn.com/2020/02/26/tech/greenhouse-gas-emissions-retail/index.html" target="_blank">says</a> the above "pattern holds true in countries where people mostly drive. It really depends on the country and consumer behavior there."</p><p>The researchers write that this year-and-a-half long study pushes back on previous research that claims online shopping to be better in terms of GHG footprints.</p><p style="margin-left: 20px;">"They have, however, compared the GHG emissions per shopping event and did not consider the link between the retail channels and the basket size, which leads to a different conclusion than that of the current study."</p><p>Online retail is where convenience trumps environment: people tend to order one item at a time when shopping on pure player sites, whereas they stock up on multiple items when visiting a store. Consumers will sometimes order a number of separate items over the course of a week rather than making one trip to purchase everything they need. </p><p>While greening efforts by online retailers are important, until a shift in consumer attitude changes, the current carbon footprint will be a hard obstacle to overcome. Amazon is trying to have it both ways—carbon-free and convenience addicted—and the math isn't adding up. If you need to order things, do it online, but try to consolidate your purchases as much as possible.</p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
Chronic irregular sleep in children was associated with psychotic experiences in adolescence, according to a recent study out of the University of Birmingham's School of Psychology.