Peering deeper into the cosmos
Multi-messenger astronomy further widens our window to the universe.
“All philosophy is but the product of two things: curiosity and shortsightedness. The problem is, we want to see more than we can."
That's how the brilliant French philosopher and provocateur Bernard Le Bovier de Fontenelle defined the central issue of natural philosophy (a.k.a. natural science) in 1686.
He was right on. We can tell the history of science as a concerted effort to expand our views of the world, opening new windows to physical reality: telescopes for the very large, microscopes for the very small, and a plethora of their descendants that scientists use in their everyday research. Instruments are tools to sate our curiosity and improve our shortsightedness. The better and more precise they are, the deeper we can see into the nature of things.
When Galileo pointed the telescope to the skies in 1609, our view of the cosmos was enlarged in ways no one could have predicted. Galileo saw features that were previously inaccessible to the naked eye, things that helped change the then dominant Aristotelian worldview of an Earth-centered universe: mountains and craters on the moon, phases of Venus, four moons orbiting Jupiter, sunspots, etc. After Galileo, telescopes grew bigger and more powerful, and the cosmos proved to be every bit as amazing and surprising as one had hoped.
Roughly up to the mid-twentieth century, most of the information astronomers gathered from the skies came in what we now call the “visible" electromagnetic spectrum, that is, the kinds of light that our eyes can see, bracketed between the colors of the rainbow, from red to violet. We can think of telescopes as “light buckets," instruments capable of capturing the light created by a variety of different physical phenomena—from Jupiter and its moons simply reflecting sunlight, to the dramatic dance of matter and radiation near black holes in distant galaxies.
In recent decades, we have witnessed an enormous expansion of our telescopic capabilities, with instruments that can capture all kinds of electromagnetic waves beyond what our eyes can see: from long wavelength to short, the list includes radio waves, microwaves, infrared, ultraviolet, X-rays, and gamma rays. Each of these kinds of radiation is generated in specific ways—for example, as matter is churned inside stars or as very distant sources get their energies “redshifted" (wavelengths get stretched) by the expansion of the universe. Usually, the shorter the wavelength of the radiation, the more dramatic the event that generated it, although, for distant sources, the drama may be attenuated by the cosmic stretching.
Until a little over two years ago, that was all we could do with astronomy (which is quite a lot indeed!)—observe objects through the range of the electromagnetic spectrum. Then, in September 2015, a completely new window to the skies was opened with the first detection of gravitational waves, the very subtle wiggling of space due to some formidable event involving extremely powerful gravitational fields. The first detection was from a collision of two huge black holes, with 36 and 29 solar masses.
A few other detections of black hole collisions followed, until another new window was opened in October 2017, of a collision of two neutron stars. It's good to recall that black holes, neutron stars, and white dwarfs are the three possible remnants of dying stars. The fate of a star (that is, what kind of object it will become after it exhausts its nuclear fuel) depends on its mass. Our sun, being a relatively light star, will become a white dwarf in about five billion years. Stars about eight to twenty times the mass of the sun end up as neutron stars, while heavier stars become black holes. (There are many technical subtleties with these ranges, but they give the reader an idea.)
The neutron star collision was exciting on a couple of fronts. First, it was the first time gravitational waves were measured from this kind of event. And second, the collision and its aftermath was observed in electromagnetic waves across the whole spectrum (from radio to gamma rays), combining information from 70 telescopes around the world and in space. This joint observation started a new kind of astronomy called “multi-messenger astronomy"—the messengers being the vibrations of space and the many kinds of radiation (light) the collision produced. Astronomers could now see the universe jointly through gravitational waves and electromagnetic radiation.
A new multi-messenger event
A week ago, it was with great excitement that astronomers and physicists celebrated the first joint observation of another kind of multi-messenger event, now combining electromagnetic waves and particles that traveled all the way from their distant source to Earth. Such particles, known as cosmic rays, rain down from the skies continuously. Usually, they consist of protons, electrons, or light atomic nuclei coming from the sun or, occasionally, from more exotic and distant sources.
Another particle that takes active part in this cosmic ray bombardment is the elusive neutrino. With very tiny masses and no charge, neutrinos (they come in 3 types) are notoriously difficult to detect; they're often called ghost particles for their ability to go through solid matter without a single collision. Every second, billions of neutrinos traveling from the sun go through your body, without you having a clue that this is happening. Talk about shortsightedness.
The new multi-messenger observation involved a blazar, the name given to a giant black hole in the center of a galaxy and its surrounding region, rich with tremendous amounts of radiation, particles, and very strong magnetic fields. Think of a rotating disk of stuff (the matter around the black hole) and a pencil going through its center (the magnetic field). The magnetic fields focus the electrically-charged particles surrounding the black hole, accelerating them away at tremendous speeds. Neutrinos are created as these particles collide and radiate their energies along the way. If the beam happens to point in Earth's direction, we get to detect it and, if we are lucky, some of the particles coming from it.
On September 22, 2017, a neutrino hit the IceCube Neutrino Observatory, a detector buried under the ice in Antarctica. The amazing thing here is that this neutrino had an enormous energy, about ten times that of particles in our most powerful accelerators. IceCube scientists sent an alert to other astronomy groups, including the approximate location of the neutrino source.
A few days after the IceCube detection, X-ray and gamma-ray telescopes confirmed emission from the same location as the super high-energy neutrino. A few days later, both optical and radio telescopes confirmed the source as a blazar about 4 billion light years away from Earth. This means that this particle traveled for about 4 billion years before it hit the ice in Antarctica. For perspective, when the neutrino left the blazar, Earth was still a baby, a churning inferno of boiling rocks and gases.
In just three years, astronomers joined forces with gravitational and particle physicists to produce a new way to look at the skies. Networking different instruments to observe celestial phenomena is now the norm, each one giving a piece of the puzzle to help create a clearer map of reality.
If this pace of discovery continues, we should be in for a very exciting decade ahead of us, no doubt full of unexpected surprises.
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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 class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgwMS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY3NDg5NTg1NX0.kdBYMvaEzvCiJjcLEPgnjII_KVtT9RMEwJFuXB68D8Q/img.png?width=980" id="59914" width="429" height="350" data-rm-shortcode-id="b11e4be64c5e1f58bf4417d8548bedc7" 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 class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgwNy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzMzQ1NjUwMn0.dVor41tO_NeLkGY9Tx46SwqhSVaA8HZQmQAp532xLxA/img.jpg?width=980" id="879be" width="1920" height="2560" data-rm-shortcode-id="4089a32ea9fbb1a0281db14332583ccd" 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 class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgxMi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0ODUyNjA1MX0.8RuU-OSRf92wQpaPPJtvFreOVvicEwn39_jnbegiUOk/img.jpg?width=980" id="687a0" width="819" height="1072" data-rm-shortcode-id="ff5edf0a698e0681d11efde1d7872958" 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 class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMxNC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNzEyNTc2Nn0.aVMa5fsKgiabW5vkr7BOvm2pmNKbLJF_50bwvd4aRo4/img.jpg?width=980" id="d8420" width="1440" height="960" data-rm-shortcode-id="8827e55511c8c3aed8c36d21b6541dbd" 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 class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMxNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY3MzQwMjc3N30.nBGAfc_O9sgyK_lOUo_MHzP1vK-9kJpohLlj9ax1P8s/img.jpg?width=980" id="9a2f6" width="1440" height="1440" data-rm-shortcode-id="4fe28368d2ed6a91a4c928d4254cc02a" data-rm-shortcode-name="rebelmouse-image" />
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 class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMyMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjY0MDY5NX0.OSwReKLmNZkbAS12-AvRaxgCM7zyukjQUaG4vmhxTtM/img.jpg?width=980" id="8804c" width="1440" height="960" data-rm-shortcode-id="67542ee1c5a85807b0a7e63399e44575" 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>
Ultimately, this is a fight between a giant reptile and a giant primate.
The 2021 film “Godzilla vs. Kong" pits the two most iconic movie monsters of all time against each other. And fans are now picking sides.
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