Lifeboat Foundation

Thank you to Squarespace for supporting PBS. Go to https://www.squarespace.com/pbs for a free trial, and when you are ready to launch, go to Squarespace.com/PBS to save 10% off your first purchase of a website or domain.

PBS Member Stations rely on viewers like you. To support your local station, go to: http://to.pbs.org/DonateSPACE

Continue reading “What If Humanity Is Among The First Spacefaring Civilizations?” »

As in physics, paradoxes in biology really are just unsolved puzzles. Enter Peto’s paradox. Biologist Richard Peto noticed in the 1970s that mice had a much higher rate of cancer than humans do, which doesn’t make any sense. Humans have over 1,000 times as many cells as mice, and cancer is simply a rogue cell that goes on multiplying out of control. One would expect humans to be more likely to get cancer than smaller creatures such as mice. This paradox occurs across all species, too: blue whales are much less likely to get cancer than humans, even though they have many more cells in their bodies.

Fermi paradox

Continue reading “10 Paradoxes That Will Stretch Your Mind” »

Physicists are devising clever new ways to exploit the extreme sensitivity of gravitational wave detectors like LIGO. But so far, they’ve seen no signs of exotica.

Earth’s low orbit is filling up, meaning radiation-tolerant cell designs are required as satellites head to higher orbits. Will these new ones do?

Scientists have developed a radiation-tolerant photovoltaic cell design that features an ultrathin layer of light-absorbing material. According to a new study published today (Nov .08) in the Journal of Applied Physics by AIP Publishing.

Significantly, the ultra-thin solar cells not only surpass earlier suggested thicker solar cells in resilience to irradiation; they also produce the same amount of power from converted sunlight after 20 years of use. Additionally, the novel photovoltaic cells could reduce load and considerably lower launch expenses. Barthel.

You can imagine starting at the beginning, evolving the Universe forward according to the laws of physics, and measuring those earliest signals and their imprints on the Universe to determine how it has expanded over time. Alternatively, you can imagine starting here and now, looking out at the distant objects as we see them receding from us, and then drawing conclusions as to how the Universe has expanded from that.

Both of these methods rely on the same laws of physics, the same underlying theory of gravity, the same cosmic ingredients, and even the same equations as one another. And yet, when we actually perform our observations and make those critical measurements, we get two completely different answers that don’t agree with one another. This is, in many ways, the most pressing cosmic conundrum of our time. But there’s still a possibility that no one is mistaken and everyone is doing the science right. The entire controversy over the expanding Universe could go away if just one new thing is true: if there was some form of “early dark energy” in the Universe. Here’s why so many people are compelled by the idea.

Contact electrification (CE) was humanity’s earliest and sole source of electricity until about the 18th century, but its real nature remains a mystery. Today, it is regarded as a critical component of technologies such as laser printers, LCD production processes, electrostatic painting, plastic separation for recycling, and more, as well as a major industrial hazard (damage to electronic systems, explosions in coal mines, fires in chemical plants) due to the electrostatic discharges (ESD) that accompany CE. A 2008 study published in Nature found that in a vacuum, ESDs of a simple adhesive tape are so powerful that they generate enough X-rays to take an X-ray image of a finger.

For a long time, it was believed that two contacting/sliding materials charge in opposing and uniform directions. However, after CE, it was discovered that each of the separated surfaces carries both (+) and (-) charges. The formation of so-called charge mosaics was attributed to experiment irreproducibility, inherent inhomogeneities of contacting materials, or the general “stochastic nature” of CE.

What is driving the mulitverse theory? Are the multiverse stories only a sticky-plaster solution to the Big Bang theory problem? Leading thinkers Sabine Hossenfelder, Roger Penrose and Michio Kaku debate.

00:00 Introduction.
02:22 Michio Kaku | Multiverse theory has now dominating cosmology; it is unavoidable.
06:03 Sabine Hossenfelder | Believing in the multiverse is the logical equivalent to believing in God.
07:57 Roger Penrose | Universes are sequential and so are not independent worlds.
16:36 Theme 1 | Do scientifc theories need to be testable?
28:45 Theme 2 | Are tales of the multiverse solutions to the Big Bang theory in trouble?
42:49 Theme 3 | Will theories of the universe always be bound by untestable elements?

Continue reading “Should we abandon the multiverse theory? | Sabine Hossenfelder, Roger Penrose, Michio Kaku” »

Sean Carroll: We might solve free will one day. But here’s why I doubt it.

Up next, The great free will debate ► https://youtu.be/3O61I0pNPg8

Continue reading “Does free will violate the laws of physics? | Sean Carroll” »

Sometimes astrophysics gets super weird.

A recent study of the star’s surface, published in the journal Nature Astronomy, says that we’re seeing Gamma Columbae in a short, deeply weird phase of a very eventful stellar life, one that lets astronomers look directly into the star’s exposed heart.

What’s New – The mix of chemical elements on the surface of Gamma Columbae look like the byproducts of nuclear reactions that should be buried in the depths of a massive star, not bubbling on its surface.