CLOSE

Lectures for a New Year: 2011 Isaac Asimov Memorial Debate (The Theory of Everything)

Time for some fairly deep physics -- strap yourselves in! For many decades, notions of a "theory of everything" have floated around scientific circles: can the universe be explained by a "unified theory," in other words a theory that unifies the theories of general relativity and quantum mechanics? Each of these theories works well in their realms (the very big and the very small), but trying to tie them together doesn't work easily. String theory is one of several possible ways to do this -- but there are others, and they all lack much in the way of testable proof. Some scientists continue to think that a unified theory is impossible.

On March 7, 2011, a six-member panel of scientists joined Neil deGrasse Tyson to discuss that elusive "theory of everything." For about an hour and a half, this distinguished group tears it up:

Dr. Katherine Freese, professor of physics at the University of Michigan

Dr. Jim Gates, professor of physics at the University of Maryland-College Park

Dr. Janna Levin, professor of physics and astronomy at Barnard College

Dr. Marcello Gleiser, professor of physics and astronomy at Dartmouth College

Dr. Brian Greene, professor of physics and mathematics at Columbia University

Dr. Lee Smolin, theoretical physicist at Perimeter Institute for Theoretical Physics

Topics: a report from Brian Greene on string theory (ten years after the first such panel), a discussion of the core problem(s) at hand, chirality, data is always just a year away, balloons, Flatland, gravitons, Adinkra symbols, and many other topics. To paraphrase what reader James said earlier this week in suggesting this discussion, the most bizarre and engaging part of this talk is when Dr. Gates raises the possibility that we all may indeed live in some form of The Matrix and are ourselves basically just mathematical/computer code. Want to know what's up with that? Watch.

For: science/physics nerds. The talk is aimed at the layman, though it may seem fairly technical to non-nerds.

Representative Quote: "Science is not about what's true or what might be true, science is about what people with originally diverse viewpoints can be forced to believe by the weight of public evidence." -Lee Smolin

Viewing tip: the introductions are nice, and they explain each panelist's background (two are high school dropouts!), but they are eminently skippable. If you want to get right into the discussion, skip ahead to about 17:00.

Further Reading

Several of these panelists, and NDT himself, have written great books. I'd recommend Brian Greene's books The Fabric of the Cosmos and The Hidden Reality.

Transcript

I haven't found a transcript of this discussion, and the auto-captions are awful. If you locate a good transcript, please point it out in the comments.

Suggest a Lecture

Got a favorite lecture? Is it online in some video format? Leave a comment and we'll check it out! Many thanks to reader James for suggesting this one.

nextArticle.image_alt|e
Mario Tama, Getty Images
arrow
science
Hawaii's Kilauea Volcano Is Causing Another Explosive Problem: Laze
Mario Tama, Getty Images
Mario Tama, Getty Images

Rivers of molten rock aren't the only thing residents near Hawaii's Kilauea volcano have to worry about. Lava from recent volcanic activity has reached the Pacific Ocean and is generating toxic, glass-laced "laze," according to Honolulu-based KITV. Just what is this dangerous substance?

Molten lava has a temperature of about 2000°F, while the surrounding seawater in Hawaii is closer to 80°F. When this super-hot lava hits the colder ocean, the heat makes the water boil, creating powerful explosions of steam, scalding hot water, and projectile rock fragments known as tephra. These plumes are called lava haze, or laze.

Though it looks like regular steam, laze is much more dangerous. When the water and lava combine, and hot lava vaporizes seawater, a series of reactions causes the formation of toxic gas. Chloride from the sea salt mixes with hydrogen in the steam to create a dense, corrosive mixture of hydrochloric acid. The vapor forms clouds that then turn into acid rain.

Laze blows out of the ocean near a lava flow
USGS

That’s not the only danger. The lava cools down rapidly, forming volcanic glass—tiny shards of which explode into the air along with the gases.

Even the slightest encounter with a wisp of laze can be problematic. The hot, acidic mixture can irritate the skin, eyes, and respiratory system. It's particularly hazardous to those with breathing problems, like people with asthma.

In 2000, two people died in Hawaii Volcanoes National Park from inhaling laze coming from an active lava flow.

The problem spreads far beyond where the lava itself is flowing, pushing the problem downwind. Due to the amount of lava flowing into the ocean and the strength of the winds, laze currently being generated by the Kilauea eruptions could spread up to 15 miles away, a USGS geologist told Reuters.

[h/t Forbes]

nextArticle.image_alt|e
iStock
arrow
Big Questions
Do Bacteria Have Bacteria?
iStock
iStock

Drew Smith:

Do bacteria have bacteria? Yes.

We know that bacteria range in size from 0.2 micrometers to nearly one millimeter. That’s more than a thousand-fold difference, easily enough to accommodate a small bacterium inside a larger one.

Nothing forbids bacteria from invading other bacteria, and in biology, that which is not forbidden is inevitable.

We have at least one example: Like many mealybugs, Planococcus citri has a bacterial endosymbiont, in this case the β-proteobacterium Tremblaya princeps. And this endosymbiont in turn has the γ-proteobacterium Moranella endobia living inside it. See for yourself:

Fluorescent In-Situ Hybridization confirming that intrabacterial symbionts reside inside Tremblaya cells in (A) M. hirsutus and (B) P. marginatus mealybugs. Tremblaya cells are in green, and γ-proteobacterial symbionts are in red. (Scale bar: 10 μm.)
Fluorescent In-Situ Hybridization confirming that intrabacterial symbionts reside inside Tremblaya cells in (A) M. hirsutus and (B) P. marginatus mealybugs. Tremblaya cells are in green, and γ-proteobacterial symbionts are in red. (Scale bar: 10 μm.)

I don’t know of examples of free-living bacteria hosting other bacteria within them, but that reflects either my ignorance or the likelihood that we haven’t looked hard enough for them. I’m sure they are out there.

Most (not all) scientists studying the origin of eukaryotic cells believe that they are descended from Archaea.

All scientists accept that the mitochondria which live inside eukaryotic cells are descendants of invasive alpha-proteobacteria. What’s not clear is whether archeal cells became eukaryotic in nature—that is, acquired internal membranes and transport systems—before or after acquiring mitochondria. The two scenarios can be sketched out like this:


The two hypotheses on the origin of eukaryotes:

(A) Archaezoan hypothesis.

(B) Symbiotic hypothesis.

The shapes within the eukaryotic cell denote the nucleus, the endomembrane system, and the cytoskeleton. The irregular gray shape denotes a putative wall-less archaeon that could have been the host of the alpha-proteobacterial endosymbiont, whereas the oblong red shape denotes a typical archaeon with a cell wall. A: archaea; B: bacteria; E: eukaryote; LUCA: last universal common ancestor of cellular life forms; LECA: last eukaryotic common ancestor; E-arch: putative archaezoan (primitive amitochondrial eukaryote); E-mit: primitive mitochondrial eukaryote; alpha:alpha-proteobacterium, ancestor of the mitochondrion.

The Archaezoan hypothesis has been given a bit of a boost by the discovery of Lokiarcheota. This complex Archaean has genes for phagocytosis, intracellular membrane formation and intracellular transport and signaling—hallmark activities of eukaryotic cells. The Lokiarcheotan genes are clearly related to eukaryotic genes, indicating a common origin.

Bacteria-within-bacteria is not only not a crazy idea, it probably accounts for the origin of Eucarya, and thus our own species.

We don’t know how common this arrangement is—we mostly study bacteria these days by sequencing their DNA. This is great for detecting uncultivatable species (which are 99 percent of them), but doesn’t tell us whether they are free-living or are some kind of symbiont. For that, someone would have to spend a lot of time prepping environmental samples for close examination by microscopic methods, a tedious project indeed. But one well worth doing, as it may shed more light on the history of life—which is often a history of conflict turned to cooperation. That’s a story which never gets old or stale.

This post originally appeared on Quora. Click here to view.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios