from the world's big
Is the speed of light slowing down?
Several things in nature go faster than the speed of light, without challenging general relativity.
Modern physics rests on the foundational notion that the speed of light is a constant, which in a vacuum is 186,000 miles per second (299,792 km/s). Einstein established this within his theory of general relativity, first developed in 1906 when he was just 26 years-old. But what if it doesn’t? A few albeit controversial incidents in recent years challenge the idea that light always travels at a constant speed. And in fact, we've known for a long time that there are several phenomena that travel faster than light, without violating the theory of relativity.
For instance, whereas traveling faster than sound creates a sonic boom, traveling faster than light creates a "luminal boom." Russian scientist Pavel Alekseyevich Cherenkov discovered this in 1934, which won him the Nobel Prize in Physics in 1958. Cherenkov radiation can be observed in the core of a nuclear reactor. When the core is submerged in water to cool it, electrons move through the water faster than the speed of light, causing a luminal boom.
On another front, while no particle with mass can travel faster than light, the fabric of space can and does. According to Inflation Theory, immediately after the Big Bang, the universe doubled in size and then doubled again, in less than a trillionth of a trillionth of a second, much faster than the speed of light. More recently, astronomers have discovered that some galaxies, the distant ones anyway, move away from us faster than light speed, supposedly, pushed along by dark energy. The best estimate for the rate of acceleration for the universe is 68 kilometers per second per megaparsec.
Quantum entanglement is another example of a faster-than-light interaction that doesn’t violate Einstein’s theory. When two particles are entangled, one can travel to its partner instantaneously, even if its mate is on the other side of the universe. Einstein called this, "Spooky action at a distance." The last example is a theoretical one (at least for now). If we were somehow able to warp or fold space-time, such as with a wormhole, it would allow a spacecraft to pass instantaneously from one side of space to another.
Credit: NASA/WMAP Science Team.
Einstein says that light acts pretty much the same throughout the universe. There’s a problem though. Today, scientists marvel at just how homogenous the universe is. One way we can tell, is by investigating the cosmic microwave background (CMB). This is essentially the light left over from the Big Bang, located in every corner of the universe.
No matter where you examine it, it’s always the same temperature, -454 Fº (-270 Cº). If that’s the case and light travels at a constant speed, how could it have made it from one edge of the universe to the other? To date, scientists have no idea, other than to say, some peculiar conditions must have existed in that early “inflation field.”
The idea of light slowing down over time was first proposed by Professor João Magueijo, from Imperial College London and his colleague, Dr. Niayesh Afshordi, of the Perimeter Institute in Canada. Their paper was submitted to Astrophysics in late 1998 and published shortly thereafter. Unfortunately, the proper instrumentation necessary to investigate the CMB to search for clues supporting it, wasn’t available at the time.
Magueijo and Afshordi eliminated the inflation field altogether. Instead, they argue that the intense heat that existed when the universe was young, ten thousand trillion trillion Cº, allowed particles—including photons (light particles), to move at an infinite speed. Light therefore traveled to every point in the universe, causing a uniformity in the CMB that we can observe today. “We can say what the fluctuations in the early universe would have looked like,” Afshordi told The Guardian, “and these are the fluctuations that grow to form planets, stars, and galaxies.” An experiment the following year lent credence to Magueijo and Afshordi’s theory.
The cosmic microwave background. Credit: NASA/WMAP Science Team.
In 1999, Lene Vestergaard Hau at Harvard stunned the world, after she conducted an experiment where she slowed light down to just under 40 mph (64 kph). Hau studies materials at a few degrees above absolute zero. In such an environment, atoms move very slowly. They begin to overlap, turning into what’s known as the Bose-Einstein condensate. Here, the atoms become one big cloud, and behave like one giant atom.
Hau shot two lasers through such a cloud, comprised of sodium atoms 0.008 inches (0.2 mm) wide. The first blast changed the quantum nature of the cloud. This increased the cloud’s refractive index, which slowed the second beam to 38 mph (61 kph). Refraction is when light or radio waves are bent or distorted when passing from one medium into another.
A discovery in 2001 also lent credence to the variable light theory. The eminent astronomer John Webb made an observation while studying quasars in deep space. Quasars are luminescent bodies billions of times as massive as our sun, which are powered by black holes. Its luminosity comes from an accretion disk, made up of gas, enveloping it.
Webb found that one particular quasar when nearing interstellar clouds, absorbed a different type of photon than would’ve been predicted. Only two things could explain this. Either its charge had changed or the speed of light had. In 2002 an Australian team, led by theoretical physicist Paul Davies, found that it couldn’t have changed polarity, as this would’ve violated the Second Law of Thermodynamics.
Artist’s impression of the quasar 3C 279. Credit: NASA Blueshift, Flickr.
Another breakthrough study in 2015 further challenged this staple of science. Scottish physicists from Glasgow and Heriot-Watt universities successfully slowed a photon at room temperature, without refraction. They basically built a racetrack for photons. It was made so that two photons raced side-by-side.
One track was unencumbered. The other held a “mask” which resembled a target with a bullseye. In the center was a passageway so narrow, the photon had to change shape to squeeze through. It slowed that photon down about one micron (micrometer), not a lot, but enough to prove that light doesn’t always travel at a constant speed.
By now, instrumentation had improved to the point where the CMB can be successfully probed. As such, in 2016 João Magueijo and Niayesh Afshordi published another paper, this time in the journal Physical Review D. They are currently measuring different areas of the CMB, and studying the distribution of galaxies, seeking clues to support their claim that light in the universe's earliest moments broke free of it's presumed speed limit.
Again, this is a fringe theory. And yet, the implications are astounding. "The whole of physics is predicated on the constancy of the speed of light," Magueijo told Vice’s Motherboard. "So we had to find ways to change the speed of light without wrecking the whole thing." Their calculations should be complete by 2021.
Want to learn more about the speed of light and whether it’s actually a constant, Click here.
Emotional intelligence is a skill sought by many employers. Here's how to raise yours.
- Daniel Goleman's 1995 book Emotional Intelligence catapulted the term into widespread use in the business world.
- One study found that EQ (emotional intelligence) is the top predictor of performance and accounts for 58% of success across all job types.
- EQ has been found to increase annual pay by around $29,000 and be present in 90% of top performers.
Evolution doesn't clean up after itself very well.
- An evolutionary biologist got people swapping ideas about our lingering vestigia.
- Basically, this is the stuff that served some evolutionary purpose at some point, but now is kind of, well, extra.
- Here are the six traits that inaugurated the fun.
The plica semilunaris<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgwMS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYxMTgyMzg1NX0.ZY8qmhtoZfbRMAqrNnmbgyk7GLabglx_9lBq3PKcy7g/img.png?width=980" id="99882" class="rm-shortcode" data-rm-shortcode-id="68e8758894b0359c6ef61b2c158832b2" data-rm-shortcode-name="rebelmouse-image" />
The human eye in alarming detail. Image source: Henry Gray / Wikimedia commons<p>At the inner corner of our eyes, closest to the nasal ridge, is that little pink thing, which is probably what most of us call it, called the caruncula. Next to it is the plica semilunairs, and it's what's left of a third eyelid that used to — ready for this? — blink horizontally. It's supposed to have offered protection for our eyes, and some birds, reptiles, and fish have such a thing.</p>
Palmaris longus<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgwNy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzMzQ1NjUwMn0.dVor41tO_NeLkGY9Tx46SwqhSVaA8HZQmQAp532xLxA/img.jpg?width=980" id="879be" class="rm-shortcode" data-rm-shortcode-id="970e9c15f3c3d846dde05e2b2c6ebf12" data-rm-shortcode-name="rebelmouse-image" />
Palmaris longus muscle. Image source: Wikimedia commons<p> We don't have much need these days, at least most of us, to navigate from tree branch to tree branch. Still, about 86 percent of us still have the wrist muscle that used to help us do it. To see if you have it, place the back of you hand on a flat surface and touch your thumb to your pinkie. If you have a muscle that becomes visible in your wrist, that's the palmaris longus. If you don't, consider yourself more evolved (just joking).</p>
Darwin's tubercle<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgxMi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0ODUyNjA1MX0.8RuU-OSRf92wQpaPPJtvFreOVvicEwn39_jnbegiUOk/img.jpg?width=980" id="687a0" class="rm-shortcode" data-rm-shortcode-id="b38a957408940673ccc744f0f6828d18" data-rm-shortcode-name="rebelmouse-image" />
Darwin's tubercle. Image source: Wikimedia commons<p> Yes, maybe the shell of you ear does feel like a dried apricot. Maybe not. But there's a ridge in that swirly structure that's a muscle which allowed us, at one point, to move our ears in the direction of interesting sounds. These days, we just turn our heads, but there it is.</p>
Goosebumps<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMxNC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNzEyNTc2Nn0.aVMa5fsKgiabW5vkr7BOvm2pmNKbLJF_50bwvd4aRo4/img.jpg?width=980" id="d8420" class="rm-shortcode" data-rm-shortcode-id="f735418322b34382dcd882299c9ccc48" data-rm-shortcode-name="rebelmouse-image" />
Goosebumps. Photo credit: Tyler Olson via Shutterstock<p>It's not entirely clear what purpose made goosebumps worth retaining evolutionarily, but there are two circumstances in which they appear: fear and cold. For fear, they may have been a way of making body hair stand up so we'd appear larger to predators, much the way a cat's tail puffs up — numerous creatures exaggerate their size when threatened. In the cold, they may have trapped additional heat for warmth.</p>
Tailbone<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMxNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMDMzMDc3N30.p9BEtkf3-PV3EtDSQMUGUeopsimiCHUagx97P4f8IBw/img.jpg?width=980" id="e8ab8" class="rm-shortcode" data-rm-shortcode-id="0063ce99bdd22fbebe1279244b87935c" data-rm-shortcode-name="rebelmouse-image" />
Coccyx. Image source: decade3d-anatomy online via Shutterstock<p>Way back, we had tails that probably helped us balance upright, and was useful moving through trees. We still have the stump of one when we're embryos, from 4–6 weeks, and then the body mostly dissolves it during Weeks 6–8. What's left is the coccyx.</p>
The palmar grasp reflex<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMyMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjY0MDY5NX0.OSwReKLmNZkbAS12-AvRaxgCM7zyukjQUaG4vmhxTtM/img.jpg?width=980" id="8804c" class="rm-shortcode" data-rm-shortcode-id="45469ca5ee5f43433a782f7d4ac0a440" data-rm-shortcode-name="rebelmouse-image" />
Palmar reflex activated! Photo credit: Raul Luna on Flickr<p> You've probably seen how non-human primate babies grab onto their parents' hands to be carried around. We used to do this, too. So still, if you touch your finger to a baby's palm, or if you touch the sole of their foot, the palmar grasp reflex will cause the hand or foot to try and close around your finger.</p>
Other people's suggestions<p>Amir's followers dove right in, offering both cool and questionable additions to her list. </p>
Fangs?<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Lower mouth plate behind your teeth. Some have protruding bone under the skin which is a throw back to large fangs. Almost like an upsidedown Sabre Tooth.</p>— neil crud (@neilcrud66) <a href="https://twitter.com/neilcrud66/status/1085606005000601600?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Hiccups<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Sure: <a href="https://t.co/DjMZB1XidG">https://t.co/DjMZB1XidG</a></p>— Stephen Roughley (@SteBobRoughley) <a href="https://twitter.com/SteBobRoughley/status/1085529239556968448?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Hypnic jerk as you fall asleep<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">What about when you “jump” just as you’re drifting off to sleep, I heard that was a reflex to prevent falling from heights.</p>— Bann face (@thebanns) <a href="https://twitter.com/thebanns/status/1085554171879788545?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script> <p> This thing, often called the "alpha jerk" as you drop into alpha sleep, is properly called the hypnic jerk,. It may actually be a carryover from our arboreal days. The <a href="https://www.livescience.com/39225-why-people-twitch-falling-asleep.html" target="_blank" data-vivaldi-spatnav-clickable="1">hypothesis</a> is that you suddenly jerk awake to avoid falling out of your tree.</p>
Nails screeching on a blackboard response?<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Everyone hate the sound of fingernails on a blackboard. It's _speculated_ that this is a vestigial wiring in our head, because the sound is similar to the shrill warning call of a chimp. <a href="https://t.co/ReyZBy6XNN">https://t.co/ReyZBy6XNN</a></p>— Pet Rock (@eclogiter) <a href="https://twitter.com/eclogiter/status/1085587006258888706?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Ear hair<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Ok what is Hair in the ears for? I think cuz as we get older it filters out the BS.</p>— Sarah21 (@mimix3) <a href="https://twitter.com/mimix3/status/1085684393593561088?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Nervous laughter<blockquote class="twitter-tweet" data-lang="en"><p lang="en" dir="ltr">You may be onto something. Tooth-bearing with the jaw clenched is generally recognized as a signal of submission or non-threatening in primates. Involuntary smiling or laughing in tense situations might have signaled that you weren’t a threat.</p>— Jager Tusk (@JagerTusk) <a href="https://twitter.com/JagerTusk/status/1085316201104912384?ref_src=twsrc%5Etfw">January 15, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Um, yipes.<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Sometimes it feels like my big toe should be on the side of my foot, was that ever a thing?</p>— B033? K@($ (@whimbrel17) <a href="https://twitter.com/whimbrel17/status/1085559016011563009?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Get 11 hours of proven techniques on candlestick, day trading, and investment.
- Becoming a successful trader involves learning the psychology tricks of the trade.
- Risk management and a winning mindset can help you maximize profits in the market.
- Simple technical and fundamental analysis strategies can help you consistently profit.
Are there innate differences between female and male brains?
People have searched for sex differences in human brains since at least the 19th century, when scientist Samuel George Morton poured seeds and lead shot into human skulls to measure their volumes.