Category: comet

Go See A Piece Of The Comet That Taught Us Where Meteor Showers Come From

“Every year, as Earth regularly orbits the Sun, meteor showers repeatedly recur. August’s Perseids and December’s Geminids are annually spectacular, but November’s Leonids have more astronomical importance. In contrast to their typically modest show, the Leonid display is spectacular every 33¼ years. In 1833, the Leonids caused a meteor storm worldwide, producing 1,000+ meteors-per-hour. For each of the next 32 years, they were quiet, but then exploded once again in 1866.”

Many meteor showers, including the most famous ones, are rich and consistent year after year, only needing to contend with factors like the Moon, clouds, and light pollution. But the Leonids are different: for 32 consecutive years, including this year, they’ll be relatively quiet, producing somewhere around 20 meteors-per-hour at their November 18, 2019 peak. But every 33rd year or so, there will be a spectacular meteor storm associated with the Leonids, and investigating why this is so led to the comet/meteor shower connection we all learn today.

How did we figure it out, and how can you see a piece of the story for yourself? Find out today, in less than 200 words, on Mostly Mute Monday!

The Perseid Meteor Shower Is Here, And Might Foretell Humanity’s Extinction

“The Perseid meteor shower, even with a near-full Moon to contend with, should be one of the year’s most spectacular meteor showers. When you look up, scope out the northwest skies after sunset (from the northern hemisphere) and look for fast-moving streaks radiating away from near the “W” in Cassiopeia. A few dozen bright streaks per hour, even in the worst-case scenario, should still await you.

But as you watch the skies, keep in mind that there’s an enormous comet responsible for this light show, and it returns every 133 years. In just a handful of orbits, it will come closer to Earth than any reasonable person should be comfortable with. Even if it’s not Swift-Tuttle, it’s only a matter of time before an object just like it comes for us, threatening the extinction of humanity and much more. We have a choice: we can let it come, or we can be ready. Extinction by comet strike is, for the first time ever, no longer an inevitability. We just have to invest in our own cosmic safety to avoid this catastrophic fate.”

When a meteor shower comes our way, you likely look up at the sky and marvel. After all, why wouldn’t you? It’s one of the night sky’s most beautiful and natural sights. In the case of the Perseids, whose peak is just around the corner, it’s the most spectacular show of the year. Even when there’s a near-full Moon to contend with, like this year, it’s still worth taking a look at one of nature’s most wondrous occurrences.

Too bad that this one, in particular, may foretell the demise of not only humanity, but the overwhelming majority of species on Earth. The comet that created the Perseids is still coming, and it’s more dangerous than ever. Find out why.

‘Aliens’ Is Not A Scientific Explanation For Interstellar Asteroid ʻOumuamua

“We often say that extraordinary claims require extraordinary evidence, and in all of these cases the evidence is very, very ordinary indeed. It’s worth keeping our mind open to the possibility that there’s more out there in the Universe than we presently realize, but not to embrace those possibilities as likely in any way whatsoever. When you leap to explanations that are fantastic, it’s all too easy to forget about the most likely explanations, which often involve nothing more than the natural phenomena already present and well-understood in the Universe we know.

In the case of interstellar interloper ʻOumuamua, we should be looking at the natural explanations first and foremost, not speculating about something for which the only evidence is our own wishful thinking. After all, what can be asserted without evidence can — and should — be dismissed without evidence.”

When you find a new phenomenon in the Universe, one that you’ve never seen before, the opportunity to discover something new about your reality is unparalleled. Oftentimes, you’ll try to use what you know to infer what behavior you expect, but it’s usually just a first-order, naive approximation. Until you collect enough data, find enough objects that fall into the new category, and study them with the required precision and detail, you’ll merely be speculating about what’s going on.

Last year, our Solar System got a visit from an interstellar interloper, marking the first time that’s ever happened. It’s been an interesting ride, full of interesting science and fascinating findings. Which is why it’s maddening that the one time it makes news is when a couple of scientists from Harvard take off their scientist hat and run headlong into sci-fi speculations.

For what I’m sure won’t be the last time, invoking aliens as an explanation for what you don’t understand isn’t science. Don’t fall for it. Get the facts instead!

This Is Why Comets Glow An Eerie Green Color

“But even though things aren’t looking particularly good for this comet, there’s always a chance it will surprise us. Furthermore, the features that you can expect for this comet — the ion tail, the dust tail, the coma, and the nucleus — are common to practically all comets that enter our inner Solar System. When a comet gets warm enough, it creates an extended, gas-rich cloud known as a coma around its nucleus. If the coma contains carbon-nitrogen and carbon-carbon bonds, the Sun’s ultraviolet light will excite the electrons inside it, causing them to emit a green glow when they drop down in energy. And whenever you see that green glow, know that there’s a chance of the comet’s nucleus splitting apart. It may not happen this time, or even most times, but there’s a chance for a visually spectacular show. When it comes to skywatching, it’s hard to ask for more.”

We typically think of comets as frozen mixes of ice and rock, but they’re so much more. There’s dust and volatile compounds present, and when the light and heat from the Sun interacts with the surface, it kicks up molecules into a gaseous, diffuse coma. This coma then gets struck by the ultraviolet light from the Sun. The dust particles get accelerated, creating the main comet tail you’re used to, but there are gas particles in the coma that simply get kicked to higher energies. If there’s enough cyanogen (CN) and diatomic carbon (C2) molecules present, they’ll create a green color due to their atomic transitions. And whenever you see that color, know that there’s the potential for the cometary nucleus to split, creating a spectacular outburst.

This may not happen for the “Incredible Hulk” comet lighting our skies today, but there’s always a chance. Don’t miss yours!

No, Comet Tails Don’t Make Meteor Showers

“When the debris from a comet or asteroid collides with the revolving Earth, the incredibly fast relative motion causes these tiny particles to burn up in the atmosphere, producing a brilliant streak of light.

Most popular explainers attribute these showers to cometary tails, but that’s simply not true.

Tails, created by the Sun’s effect on a comet or asteroid, are pushed away from the Sun, and this material spreads out rapidly, never to collide with Earth.”

You’ve heard the simplistic explanation before: that comets emit tails, those tails collide with Earth, and that’s where meteor showers come from. It’s an explanation that even NASA has given from time to time, and it’s a complete fabrication. Meteors that you see during a meteor shower have literally zero connection to cometary or asteroidal tails, and that’s easy to show: tails are always emitted away from the Sun, so the next time this tail material orbits the Sun and comes back near Earth, it’s much farther away and won’t collide with our world at all. But there is a debris stream due to the breakup of the central core of the comet or asteroid in question, and that gets spread out along the orbit over time. When Earth passes through that debris stream, that’s where meteor showers truly come from.

Don’t miss the full story, including a slew of spectacular pictures, on this edition of Mostly Mute Monday!

Sorry, Doomsday Forecasters, Earth’s Mass Extinctions Occur At Random

“Unfortunately, it’s human nature to seek patterns wherever things occur, but in this case, the evidence is far too weak to bet against randomness in any way. It’s important to remember that just because we don’t see evidence for periodic events doesn’t mean they don’t occur, but it’s important to not go chasing after a phenomenon that doesn’t have the evidence supporting its reality. Asteroid and comet strikes may have increased likelihoods at certain times, and there may be a periodic effect for CO2 levels and the carbon crustal cycle, but neither one has any evidence linking them to mass extinctions. When it comes to catastrophic events for the planet, and the species that inhabit it, randomness is as good as it gets.”

We’ve all wondered, at some point, if the asteroid that wiped out the dinosaurs isn’t a phenomenon that might not have been completely at random, but rather caused by a periodic, cosmic occurrence. Could our motion through the galaxy cause asteroidal or cometary impacts to occur more frequently at certain times? Would those times be periodic? And if so, could it make a mass extinction event more likely at certain times? This doesn’t need to be restricted to asteroids, but could be related to periodic geological or climatic changes as well. Fortunately, we know how to analyze this type of data, and to look for patterns in whether these extinction events appear at random or at uniform spacings. In 2013, the best analysis ever of this was undertaken by Fabo Feng and Coryn Bailer-Jones. As they conclude, in their own words: “…the time distribution of mass extinction events is consistent with being randomly distributed in time. There is no need to resort to anything more exotic.”

If you wanted to forecast our natural doomsday, the Universe isn’t going to help you out. Earth’s mass extinctions occur at random, and we’ve got the scientific evidence to back it up!

Interstellar Visitor ‘Oumuamua Was Shaped By Cosmic Particles

“We think of space as being an empty place, but the truth is that there are dust grains, particles, neutral atoms, ions, and cosmic rays zipping through the entirety of the galaxy, even when there are no stars. As an object moves through space, circling the galaxy at hundreds of kilometers per second (and moving relative to most other objects at tens of kilometers per second), it’s constantly bombarded by large numbers of small, fast-moving bits of matter. Just as water and sand will smooth out and erode pebbles and cobbles in the ocean here on our world, the cosmic equivalent — the interstellar medium — will have the same effect over extremely long timescales on ejected icy bodies.”

When scientists discovered ‘Oumuamua last year, they were surprised to find that it not only originated from outside our Solar System, but possessed bizarre properties we had never seen before. It was extremely elongated, tumbled irregularly, and had a never-before-seen composition: a carbon crust over an icy interior. Despite heating up to 550 °F (290

°C), it never developed a tail, a coma, or showed any ejecta. Many have proposed exotic or recent origins for this interstellar interloper, but in this case, simplicity rules: it may just be a cosmic pebble in the galactic sea. The interstellar medium is full of particles, and ‘Oumuamua, like most interstellar objects, should move at about 0.01% the speed of light through the galaxy. Over time, it should be worn down in exactly the fashion we see. As we discover more objects with an origin beyond our Solar System, we fully expect they’ll appear quite similar to this one.

How was ‘Oumuamua shaped? Likely by cosmic particles, rather than anything exotic. Come find out the science behind how.

How Can We Tell If A Space Rock Came From Outside Our Solar System?

“But when we examined its orbital properties, a real shock came. First off, it’s highly inclined to the plane of the Solar System, something that normally only occurs for object originating from the Oort cloud or the outer Kuiper belt. An asteroid like this is virtually unheard of. Second off, it was moving fast; far too fast to have been caused by conventional means. Even if you began with this object an infinite distance away and let the full gravitational effects of the Solar System pull it in, it wouldn’t be moving this quickly. The only way to get an object moving at these tremendous speeds is with a gravitational encounter with a very massive planet: a gas giant.

But that’s where the third surprise comes in. If you trace back its orbital path, there’s no way it could have occurred that way. None of the planets encountered it in the past; it’s completely gravitationally unbound.”

On October 19th, we detected an object that was unlike anything else we’d ever seen before. It was moving too fast at too unusual of an angle to be either a comet or an asteroid, and was too thoroughly gravitationally unbound to be hurled in by a planet, whether known or unknown. Based on what we detected, there’s only one conclusion that makes sense: this object came from outside our Solar System. These interstellar interlopers have long been theorized, but this is the first time one has ever been seen. Without a tail or coma at all, it’s unique among objects that come from so far away, and yet follow-ups have verified exactly what we hoped for. This is the first object to ever have an extra-solar origin, and is likely the first of many that we’ll find.

Here are the criteria for evaluating whether something came from beyond our Solar System, and how we’ll find out even more next time!

The Comet That Created The Perseids Might Bring An End To Humanity

“Every object in our Solar System that takes the plunge from out beyond Neptune to our inner reaches, where the rocky planets lie, will become a comet. As it nears the Sun, its ices melt, creating the tails we associate with them, and also creating a debris path that can create meteor showers if they cross Earth’s orbit. For thousands of years, the most consistent, spectacular meteor shower has been the Perseids, created by Comet 109P/Swift-Tuttle

 At its incredibly large size (26 kilometers across) and speed, it contains nearly 30 times the energy of the asteroid strike that wiped out the dinosaurs. Over the next few thousand years, it will come perilously close to Earth. If Jupiter — which it also passes by — gives it just the slightest gravitational kick, it could be flung into the Sun, ejected from the Solar System, or hurtled directly into our world. If this were to happen, and it’s a real possibility some 2400 years from now, it would mark the largest mass extinction our world has seen in hundreds of millions of years.”

Enjoying the Perseid meteor shower this year, as perhaps you do every August? As you look up, the great cosmic show might have a lot more to offer than mere streaks of light, due to cometary debris brightly burning up in the Earth’s atmosphere. This year, Jupiter has slightly disturbed the debris stream, resulting in an increase in the number of meteors-per-hour, as the stream passes quite centrally through Earth’s location. Someday, unless we continue to get lucky, Jupiter just might have that same effect on the comet that spawned the Perseids: comet Swift-Tuttle. Only, instead of an enhanced shower, we’d get struck by this comet. With a top speed of 60 km/s and a size of 26 km in diameter, this would result in an impact 28 times more energetic than the impactor that wiped out the dinosaurs.

Comet Swift-Tuttle is the single most dangerous object known to humanity. Come enjoy our continued existence and learn about our possible future demise, while you still can!

How To Catch The Perseids And Beat The Almost-Full Moon

“The faintest meteors will be washed out; the brightest meteors will appear dimmer; the total rate of the shower’s peak, instead of about 100 meteors-per-hour, will be approximately halved. If you were hoping to get up early (or stay up very, very late) for a great view, you’re going to be sorely disappointed. Luckily for you, not only is the debris stream that creates the Perseids wide, but the views are quite good for a day or two before and after the peak.”

The full or almost-full Moon might be one of the most familiar sights in the night sky to those of us here on Earth, but it’s also the largest natural source of light pollution we have to contend with. The peak of this year’s Perseid meteor shower meant, if all things were equal, the best time to see the highest rate of meteors would be the pre-sunrise sky of August 12. But with a large gibbous Moon dominating the skies during that time, it’s actually one of the worst ways you can try and view the Perseids this year. Instead, go out when the skies are darkest: before the Moon rises just after the peak. Because of how wide the cometary debris stream that gives rise to the Perseids is, viewing the sky in the evening before the Moon rises on the 12th or even the 13th is a far safer bet.

Come get your fix of the great night sky views of August, just a week before the solar eclipse comes to your daytime skies!