PBS Space Time

Ever wish you could travel backward in time and do things differently? Good news: the laws of physics seem to say traveling backward in time is the same as traveling forwards. So why do we seem to be stuck in this inexorable flow towards the future? It's time to begin our journey towards really understanding time.

Physicists have a long history of sticking our noses where they don’t belong - and one of our favorite places to step beyond our expertise is the question of consciousness and free will. Sometimes our musings are insightful, sometimes incoherent, and usually at least somewhat naive. Which a fair description of this show, so of course, Space Time needs to weigh in physics and free will.

Our universe seems..complicated. We have a weird zoo of elementary particles, which interact through very different fundamental forces. But some extremely subtle clues in nature have led us to believe that the forces of nature were once unified, ruled by a single, grand symmetry. But how does one force separate into multiple? And how do the forces of nature arise from mathematical symmetries?

The 2020 Nobel prize in physics went to black holes. It was shared by the astronomers who revealed to us the Milky Way’s central black hole and by Roger Penrose, who proved that in general relativity, every black hole contains a place of infinite gravity - a singularity. But the true impact of Penrose’s singularity theorem is much deeper. it leads us to the limits of Einstein’s great theory.

Einstein’s special theory of relativity combines space and time into one dynamic, unified entity - spacetime. But if time is connected to space, could the universe be anything but deterministic? And does that mean that the future is predestined?

Is all that exists just whatever exists right now? Is the past erased and the future a void yet to be filled? Well, the answer lies in between the past and the future - in the elusive, ever-moving eye-blink that we call the present.

If you rank the most habitable places in our solar system Venus lands pretty low, with surface temperatures hot enough to melt lead and sulphuric acid rain. And yet it may have just jumped to the front of the pack. In fact, we may have detected the signature of alien life - Venusian life -for the first time.

Your search history is only a tiny math problem to becoming public knowledge. That math problem is prime number factoring, and the new era of quantum computers may lay bare your indiscretions, as well as collapse the entire digital economy. Unless we get us some post-quantum cryptography post-haste. So, how close are we?

Fundamental kinks and defects in the fabric of the universe - cosmic strings beaded with magnetic monopoles - may evolve into complex structures, and even life, within stars. This idea was just published in Letters High Energy Physics Letters by physicists Luis Anchordoqui and Eugene Chudnovsky, and today on Space Time Journal Club we’re going to see how legit this actually is.

The great physicist Hermann Weyl once said: "My work always tried to unite the true with the beautiful, but when I had to choose one or the other, I usually chose the beautiful." But is this actually good advice for doing physics?

Pin-pricks in the celestial sphere, through which shines the light of heaven? Or gods and heroes looking down from their constellations? Or lights kindled above middle earth by Varda Elbereth and brightened with the dew of the trees of Valinor? Science has long pondered the mysteries of the stars. This is how we finally figured them out.

In June 2020, the consortium of Europe’s top particle physicists published their vision for the next several years of particle physics experiments in the EU. A big part of that is the Future Circular Collider which will accelerate particles in a 100-kilometer circumference underground ring encircling Geneva. It’ll be nearly 4 times the size of the Large Hadron Collider. But will they succeed?