Mysteries of the Universe - 8 Things Modern Astronomers are still Puzzled By | S02E59

Good e everybody, and welcome to the Astronomy Daily podcast. My name is Tim Gibbs and I will be your host for today. The podcast will be now as usual, I have in a studio with me Halle, my AI digital assistant and reporter. But before we go over to Halle for the second half of the show, I'd like to talk a little bit about a couple of things that people have sent to me. One is a listical, if you like, of the eight things that modern astronomers still are puzzled by. And I think it's worth reminding ourselves that there are things out there that we really have no idea what's going on. So on with the list, and it's in no particular order. First off, what is dark energy? As we all know, astronomer Edwin Hubble discovered the universe is not static, but rather expanding in the nineteen twenties. This discovery puzzled scientists for a long time, who thought that the gravity of matter would gradually slow the universe's expansion or even cause it to contract. While dark energy is thought to make up approximately seventy three percent of the universe, the force remains elusive and yet and has yet to be directly detected dark energy might never reveal its nature. Number two How hot is dark matter? Astronomers explain this curious phenomenon with this with an invisible mass that became known as dark matter. Even though it cannot be seen, dark matter has mass, so researches infer its presence based on the gravitation gravitational pull it exerts on regular matter. Dark matter is thought to make up about twenty three percent of the universe, while only four percent of the universe is composed of regular matter, which includes stars, planets, human beings, cats and dogs, etc. Number three Where are the missing baryons? If dark matter and dark energy combined to make up roughly ninety five percent of the universe, regular matter makes up about five percent of the cosmos, Yet more than half of this regular matter is missing. Nobody knows where it is. Number four How do stars explode? When a massive star runs out of fuel and dyes, it triggers a spectacular explosion called a supernova that can briefly shine more brightly than the entire galaxy. Over the years, scientists have studied supernovas and recreated them using sophisticated computer models. But how these giant explosions occur is still an enduring astronomical puzzle. Number five, What reionize the unit? The broadly accepted theory for the origin and evolution of the universe is the Big Bang model, which states that the cosmos began as an incredibly hot, dense roughly point thirteen point seven billion years ago. A dynamic phase in the history of the early universe approximately thirteen billions years ago, is known as the age of reionization. During this period, the fog of hydrogen gas in the early universe was clearing and becoming transparent to the ultraviolet light for the first time. Number six, what's the source of the most energetic cosmic rays? The source of cosmic rays has long perplexed astronomers, who have spent a century investigating the origin of these energetic particles. Cosmic rays are charged subatomic particles, predominantly protons, electrons, and the charged nuclei of basic elements. The flow into our Solar System from deep deep in outer space as comic as cosmic rays flow into the Solar System from elsewhere in the galaxy. Their paths are bent by the magnetic fields of the Sun and the Earth. Next up, why is the Solar system so bizarre? As astronomers and space observers discover alien planets around around other stars, researchers have been keen to understand the unique chara characteristics of our Solar system. Now last, but certainly not least, why is the Sun's corona so hot? The Sun's ultra hot outer atmosphere is called the corona and is typically heated as temperatures raining from nine hundred thousand degrees fahrenheit that's five hundred thousand degrees celsius celsius to ten point eight million degrees fahrenheit six million degrees see. For the best part of a century, solar physicists have been mystified by the Sun's ability to reheat its the encircling, wispy crown of light that emerges from the glare during a solo eclipse. The second article I was sent has a headline that is basically grabbing its Pluto's almost twin dwarf planet Eris is surprisingly squishy. There you go, I told you it would grab you. New models show that Eris is behaving less like a solid, rocky world and more like soft cheese. Yeah, I know. Close to eighteen years ago, astronomers spotted a miniature icy world named Eris, billions of miles beyond Neptune. But unlike its dwarf planet cousin Pluto, which New Horizons promoted to a rich, dynamic world after its visit in twenty fifteen, Eris has not had any robotic visitors. It is so far away from Earth, in fact, that it shows up in observations just as a single pixel of light. All in all, scientists know very little about what happens on Eris. Now over to you, Hally, and I hope you've got a decent joke for us this week the Astronomy Daily podcast. Hi Tim, it's great to be back with you, and yes, I have a couple of great jokes. But first let's have some news stories from the Astronomy Daily newsletter. A new theory suggests that the unification between quantum physics and general relativity has eluded scientists for one hundred years because huge are fluctuations in space and time mean that gravity won't play by quantum rules. Since the early twentieth century, two revolutionary theories have defined our fundamental understanding of the physics that governs the universe. Quantum physics describes the physics of the small at scales tinier than the atom, telling us how fundamental particles like electrons and photons interact and are governed. General relativity, on the other hand, describes the universe at tremendous scales, telling us how planets move around stars, how stars can die and collapse to birth black holes, and how galaxies cluster together to build the largest structures in the cosmos. Since their development, these two theories have grown more robust and have bolstered science. With their tremendous success. Quantum mechanics has shown that the quantum world is replete with counterintuitive aspects, like the existence of systems simultaneously in contradictory states, or particles instantly influencing each other even at opposite ends of the universe. General relativity, meanwhile, has revealed that the very fabric of space time is shaped by the matter sitting upon it, and that violent interactions between bodies of great mass can create ripples in space time known as gravitational waves, that can travel for billions of light years to wash over Earth. Yet there is a problem, a dark cloud that hangs over these disciplines, as these two pillars of physics are perfected, scientists are still unable to bridge the gulf between them. The two pillars of modern physics are inconsistent with each other, which means that there is a fundamental contradiction which lies in the very foundation of our laws of nature. University College London UCL professor Jonathan Oppenheim said. Oppenheim is the pioneer of a new and radical theory that could finally bring together these two concepts, a reconciliation that has defied the greatest scientific minds for over one hundred years. Previously, uniting general relativity with quantum physics has meant taking spacetime, the three dimensions of space, and the one dimension of time unified as a single four D entity that is at the foundation of general relativity, and breaking it down into discrete units or quanta. This requires spacetime to be a passive stage on which that a action of the universe plays out. However, general relativity hinges on space time not being a static stage, but rather a dynamic player in the universe's cosmic ballet, shaped by the presence of matter and energy, and subsequently telling matter and energy how to move via the curvature and gravity that arises from it. Oppenheim's idea of e waving space time time is based upon asking why gravity should have a quantum nature like that which has been discovered for the universe's other fundamental forces, electromagnetism and the strong and weak nuclear forces. Gravity, he argues, isn't like these other forces. After all, it is the only one of the four that can define the very geometry of space time, and the fields of quantum physics evolve upon this geometry. We feel gravity because matter causes space time to bend. Time flows at unequal rates at different locations, Oppenheim writes in a paper discussing his theory published in the journal Physical Review X the rate at which time flows and the causal structure the fact that because always precedes effect it provides may be required to have a classical description in order for quantum theory to be well formulated. That means, according to his theory, termed it a post quantum theory of classical gravity, that space time and thus gravity don't have quantum description. That's thanks to random fluctuations in space time, which cause changes in the flow of time, thus breaking the concept of predictability. NASA marks the twenty fifth anniversary of the ISS with a live event on December sixth. The ISS operational since nineteen ninety eight, has been key to space research and exploration, hosting two hundred and seventy three astronauts and over three thousand, three hundred research projects. NASA is celebrating the twenty fifth anniversary of International Space Station operations during a live conversation with crew aboard the Microgravity Laboratory for the benefit of humanity. Space Station Program Manager DOT On December sixth, nineteen ninety eight, the first two elements of the orbital outpost, Unity and Zaria were attached by crew members of Space Shuttle Endeavours STS eighty eight mission. Cabana was the commander of the mission and the first American to enter the space station. Through this global endeavour, Astronauts have continuously lived and worked aboard the space station for more than twenty three years, testing technologies, performing science, and developing the skills needed to explore farther from Earth. It has been visited by two hundred and seventy three people from twenty one countries. More than three thousand, three hundred research and educational investigations have been conducted on station from one hundred and eight countries and areas. Many of these research and technology investigations benefit people on Earth, and many lay the groundwork for future commercial destinations in low Earth orbit and exploration farther into the Solar System. Together with Artemis missions to the Moon, these proving grounds will help prepare NASA for future human exploration of Mars. The Astronomy Daily Podcast and now some excellent jokes for you. The most scientific pet the lab? What is the cuddliest particle known to science? The hugs boson. Thanks for listening, everybody, and see you next week for another episode. Don't forget. You can get all our episodes from space Nuts dioe, and you can join in the conversation on our Space Nuts podcast group on Facebook. Bye The Astronomy Daily Podcast.