from the world's big
Is Time Travel Possible? -- Part II
As we mentioned in a previous post, Einstein himself was worried about the possibility that time travel was built into his General Theory of Relativity. In 1949, when his good friend Kurt Gödel showed that a rotating universe allowed for time travel, he was deeply worried.
Gödel, in fact, would pester astronomers visiting Princeton and ask if there was any sign that the universe was rotating. In Einstein's writings, he finally concluded that time travel might be inherent in his equations, but they can be dismissed "on physical grounds," i.e., they could not form using known physical mechanisms. In other words, the universe expanded, not rotated. So if the universe did rotate, then time travel might be an everyday occurrence. This argument holds even today. There are a large class of solutions of Einstein's equations, but many can be dismissed "on physical grounds." For example, in 1937, W.J. Van Stockum showed that a spinning cylinder that was infinitely long could satisfy all of Einstein's equations. Decades later, it was shown that the Stockum solution actually allowed for time travel. If you danced around this cosmic Maypole fast enough, you could come back before you left. But again, "on physical grounds," one can argue that cylinders can never be infinitely long, so this was just a mathematical curiosity.
Another solution allowing for time travel was found by Einstein himself, back in 1935, when he (and Nathan Rosen) introduced the wormhole. If you take the black hole solution (which looks like a funnel), cut off the end, and then join it, back-to-back, with another truncated funnel, then you have a wormhole. So at the heart of a black hole might lie a gateway to a parallel universe. In principle, you can then create wormholes connecting you to the distant past and hence create a time machine. However, "on physical grounds," you may dismiss this solution because anyone falling into a black hole would die in the process. So this was a mathematical solution, rather than a physical one.
But then, in 1963, things began to change. Mathematician Roy Kerr found perhaps one of the most beautiful exact solutions to Einstein's equations: a rotating black hole. Instead of collapsing into a dot (a singularity), the black hole was spinning rapidly, so it would shrink into a rotating ring. It did not collapse into a dot because of centrifugal force. The Kerr ring was like the Looking Glass of Alice. If you fell through the ring, you would not die at all, but fall through the wormhole into a parallel universe. If the parallel universe was your own past, then this could be used as a time machine.
Kerr himself was intrigued by what might happen if you fell into his black hole. If you fell multiple times through the ring by making circles around it, then you would pass through various parallel universes. Think of taking many parallel sheets of paper, then taking a pencil and punching a hole through all of them. Each sheet is a parallel universe, but the hole connects all of them. Passing multiple times through the Kerr ring was like pushing the "up" button on an elevator, and passing through multiple parallel universes.
One problem (among many) with the Kerr rotating black hole is that a journey through it is a one-way street. The black hole is surrounded by two (not just one) "event horizons," which are points of no return. So you would have to travel faster than the speed of light (which is not possible here) to come back to your original universe.
However, in the 1980s Kip Thorne and his colleagues at Cal Tech then found yet another solution of Einstein's equations, which allowed back-and-forth travel through a wormhole. These are called "transversable wormholes" and can be used to transport you to a different time or different point in space. You have to introduce, however, negative matter or negative energy to power this transversable wormhole.
But all of this has not yet answered the fundamental question raised by Einstein himself: are these solutions allowed "on physical grounds?" Mathematically, all of these solutions seem to work. But perhaps they are unstable, or too radioactive, to allow for genuine time travel. To answer these physical questions, we now have to go the next theory, the quantum theory, and a theory which combines relativity with the quantum theory, string theory, which is what I do for a living.
We will address this crucial but sticky question next.
Sample Melbourne's best coffee without leaving an ecological footprint.
- The massive increase in single-use coffee pods has led to an environmental catastrophe.
- Plastic pods are notorious for their inability to break down in landfills.
- Thankfully, a new wave of eco-friendly compostable pods is coming to the market.
Can an orgasm a day really keep the doctor away?
- Achieving orgasm through masturbation provides a rush of feel-good hormones (such as dopamine, serotonin and oxytocin) and can re-balance our levels of cortisol (a stress-inducing hormone). This helps our immune system function at a higher level.
- The surge in "feel-good" hormones also promotes a more relaxed and calm state of being, making it easier to achieve restful sleep, which is a critical part in maintaining a high-functioning immune system.
- Just as bad habits can slow your immune system, positive habits (such as a healthy sleep schedule and active sex life) can help boost your immune system which can prevent you from becoming sick.
How masturbation affects your brain...<p>Orgasms are a very common human phenomenon. The physical and mental health benefits have been researched frequently as a result, and yet, there is still so much to be learned about how our bodies and brains react to the chemicals and hormones released during and after experiencing this type of sexual release.</p><p>"The amount of speculation versus actual data on both the function and value of orgasm is remarkable" explains Julia Heiman, director of the <a href="https://kinseyinstitute.org/" target="_blank">Kinsey Institute for Research in Sex, Gender, and Reproduction</a>.</p><p>Masturbation causes a rush of <a href="https://www.webmd.com/mental-health/what-is-dopamine" target="_blank">dopamine</a>, which is a chemical that is associated with our ability to feel pleasure. Along with the rush of dopamine that is released during an orgasm, there is also a release of a hormone called <a href="https://www.livescience.com/42198-what-is-oxytocin.html" target="_blank">oxytocin</a>, which is commonly referred to as the "love hormone."<br></p><p>This concoction of chemicals does more than just boost our mood, it also can play a key role in decreasing stress and promoting relaxation. Oxytocin decreases <a href="https://www.webmd.com/a-to-z-guides/what-is-cortisol" target="_blank">cortisol</a>, which is a stress hormone that is usually present (in high volumes) during times of anxiety, fear, panic, or distress. </p><p>According to BDSM and fetish researcher <a href="https://www.psychologytoday.com/us/therapists/dr-gloria-brame-colbert-ga/278388" target="_blank">Dr. Gloria Brame</a>, an orgasm is the biggest non-drug induced blast of dopamine that we can experience. </p><p>By boosting the oxytocin and dopamine levels and subsequently decreasing our cortisol levels, the brain is placed in a more relaxed, euphoric, and calm state. </p>
Masturbation boosts your immune system and raises your white blood cell count.<p>How do those effects on the brain from reaching orgasm translate to boosting our immune system and making our body healthier?</p><p>The increase of oxytocin and dopamine that causes a decrease in cortisol levels can help boost our immune system because cortisol (well-known for being a stress-inducing hormone) actually helps maintain your immune system if released in small doses. </p><p>According to <a href="https://www.health24.com/Sex/Great-sex/incredible-health-benefits-to-masturbating-20181030-2" target="_blank">Dr. Jennifer Landa</a>, a hormone-therapy specialist, masturbation can produce the right kind of environment for a strengthened immune system to thrive. </p><p><a href="https://www.ncbi.nlm.nih.gov/pubmed/15316239" target="_blank">A study</a> conducted by the Department of Medical Psychology at the University Clinic of Essen (in Germany) showed similar results. A group of 11 volunteers were asked to participate in a study that would look at the effects of orgasm through masturbation on the white blood cell count and immune system.</p><p>During this experiment, the white blood cell count of each participant was analyzed through measures that were taken 5 minutes before and 45 minutes after reaching a self-induced orgasm. </p><p>The results confirmed that sexual arousal and orgasm increased the number of white blood cells, particularly the natural killer cells that help fight off infections. </p><p>The findings confirm that our immune system is positively affected by sexual arousal and self-induced orgasm and promote even more research into the positive impacts of sexual arousal and orgasm. </p>
Masturbation can ease and prevent pain, which allows you to achieve the restful sleep that helps your immune system stay strong and healthy.<p>The benefits of masturbation have long been debated, but the more research that is done on the topic the more we understand that there are many positive reactions that happen in our bodies and brains when we orgasm.</p><p>Orgasms can help prevent or mitigate pain, which boosts the immune system, preventing cold and flu symptoms. </p><p>According to neurologist and headache specialist Stefan Evers, about one in three patients experience relief from migraine attacks by experiencing sexual activity or orgasm. Evers and his team <a href="https://www.livescience.com/27642-sex-relieves-migraine-pain.html" target="_blank">conducted an experiment</a> with 800 migraine patients and 200 patients who suffered from cluster-headaches to see how their experiences with sexual activity impacted their pain levels. </p><p>The study showed that 60% of migraine sufferers experienced pain relief after participating in sexual activity that resulted in orgasm. Of the cluster-headache sufferers, about 50% said their headaches actually worsened after sexual arousal and orgasm. </p><p>Evers suggested in his findings that the people who did not experience pain relief from migraines of headaches during their sexual activity did not release as large amounts of endorphins as those who did experience pain relief. </p><p>According to <a href="https://www.sharecare.com/health/chronic-pain/chronic-pain-affect-immune-system" target="_blank">rheumatologist Dr. Harris McIlwain</a>, people who suffer from chronic pain have immune systems that are simply not functioning at full capacity - therefore, alleviating pain (through orgasm, as an example) can help boost the immune system. </p><p>Orgasms can also promote relaxation and make it easier to fall asleep. Serotonin, oxytocin, and norepinephrine are all hormones that are released during sexual arousal and orgasm, and all three are known for counteracting stress hormones and promoting relaxation, which makes it much easier for you to fall asleep.</p><p>There are <a href="https://www.ncbi.nlm.nih.gov/pubmed/1233384" target="_blank">several studies</a> showing that serotonin and norepinephrine help our body cycle through REM and deep non-REM sleeping cycles. During these sleep cycles, the immune system releases proteins called <a href="https://www.sleepfoundation.org/articles/how-sleep-affects-your-immunity" target="_blank"><span id="selection-marker-1" class="redactor-selection-marker"></span>cytokines<span id="selection-marker-2" class="redactor-selection-marker"></span></a>, which target infection and inflammation. This is a critical part of our immune response. Cytokines are both produced and released throughout our bodies while we sleep, which proves the importance of a good sleep schedule to a healthy immune system.</p>
Masturbation promotes a high-functioning immune system; a healthy immune system prevents cold and flu.<p>The immune system is a balanced network of cells and organs that work together to defend you against infections and diseases by stopped threats like bacteria and viruses from entering your system. While there are many things we need to do to keep our immune systems functioning at optimal levels, masturbation (or other means of achieving orgasm) has proven to have positive effects on the immune system as a whole.</p><p>Just as bad habits (such as an inconsistent sleep schedule or harmful chemicals in your body) can slow your immune system, positive habits (such as a healthy sleep schedule and active sex life) can help boost your immune system. </p>
Workers are adjusting to their new employment reality on couches and kitchen tables across the nation.
A new study suggests that an old tuberculosis vaccine may reduce the severity of coronavirus cases.
- A new study finds a country's tuberculosis BCG vaccination is linked to its COVID-19 mortality rate.
- More BCG vaccinations is connected to fewer severe coronavirus cases in a country.
- The study is preliminary and more research is needed to support the findings.
Professor Luis Escobar.
Credit: Virginia Tech