Category: asteroid

Goodbye ‘Oumuamua, Hello Borisov; This Is What Two Interstellar Interlopers Can Teach Us

“The most interesting aspect of what we know so far about interstellar objects is how different the first two, ‘Oumuamua and Borisov, truly are from one another. There are a number of ways to form interstellar bodies: from failed star systems in star-forming regions, from ejected asteroids, from comets, and from collisional debris. We do not know how common or rare objects of all these different types are, nor how to definitively classify the ones we’ve seen so far, but hope is on the way. Beginning in the 2020s, the Large Synoptic Survey Telescope will come online, expected to uncover dozens of such objects by 2030.

What are the size and frequency distributions of the interstellar population? How old and/or weathered are they? Are they comet-like or asteroid like; volatile-rich or volatile-free, and do different classes of object originate from different regions in the sky? Are most small objects inactive while most large ones are active? With the tip of the interstellar iceberg uncovered, the answers to these questions and more are at last within our reach.”

In our solar system, asteroids, centaurs, comets, Kuiper belt and Oort cloud objects all have their own unique story, but possess many qualities common to each separate class. Occasionally, one of these objects will get ejected, where it will wander the Milky Way indefinitely, until it encounters another object.

Back in our Solar System, we’ve begun discovering and identifying objects in our neighborhood that originated from interstellar space. In 2017, ‘Oumuamua became the first, and it was extremely odd: small, elongated, and already on its way out. Our picture is now changing dramatically, as a second interstellar object, 2I/Borisov, was just discovered.

With its closest approach coming in early December, astronomers worldwide are getting ready. Here’s what we know so far.

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.

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.

The Year’s Best Meteor Shower Is Here, And The Geminids Are Better Than Ever

“This year, at the peak of the Geminids, the Moon will be a waning crescent, not even rising until well after midnight. Even when it does, it will be thin enough and far enough away from the origin of the Geminids that you’ll still have a spectacular show. If you have dark, cloudless skies, you should be able to see up to two or three meteors per minute once the sky reaches full darkness this year. While the cold snaps affecting much of the country might make it a little unpleasant to be outside for too long, it also provides the best viewing conditions for the night sky. This year, you won’t want to pass up the opportunity.”

Every year, there are two meteor showers reliably worth checking out if the conditions are favorable: August’s Perseids and December’s Geminids. This year, with the Moon in a waning crescent phase and with clear skies anticipated across most of the country, the Geminids just might shape up to be spectacular. Created by the debris of asteroid 3200 Phaethon, the Geminids are a relatively young shower at under 200 years, and they continue to get more spectacular over time, peaking at over 150 meteors per hour the last few years. There’s an incredible scientific story behind where these showers come from, and an incredible show to be had if you can find clear, dark skies. The year’s best meteor shower is here, with the peak coming in just a few days.

Come find out how to get the most out of your Geminid experience, Don’t pass up the opportunity to see one of nature’s most spectacular shows!

Hubble Catches Asteroids Photobombing Ultra-Distant Galaxies

“There are a total of 20 objects seen in these fields, corresponding to 7 unique asteroids, most of which are imaged multiple times. Only 2 of them were previously known; the remainder were serendipitously discovered by Hubble. Approximately 10-to-20 hours of observing time leads to the discovery of a new asteroid, telling us something interesting about the density of asteroids at the level that Hubble’s imaging capabilities are sensitive to. As long as you’re observing a target close to the plane of the Solar System’s ecliptic, you’re bound to be polluted by these interlopers.”

There’s an old saying among astronomers: one astronomer’s noise is another astronomer’s data. If you’re trying to view the galactic center, then the interstellar medium is “noise,” but if you’re studying the interstellar medium, then that’s exactly the data you want! Well, a team studying the massive galaxy cluster Abell 370 got to do a very long, deep-exposure image of both that cluster and its parallel field, accumulating a total of nearly 100 hours of observing time. As it so happens, this cluster happens to lie very close to the Solar System’s ecliptic plane, meaning that objects in the asteroid belt occasionally cross through Hubble’s field-of-view. Although it would take tens of millions of Hubble images to cover the entire sky, there are millions of asteroids bright enough for Hubble to see, and a few of them “photobombed” both the galaxy cluster and its parallel field.

We can produce cleaned images without them in the end, but the extragalactic astronomer’s noise is the asteroid hunter’s data! Come get the story, and see the remarkable photos, today!

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!

Are Mass Extinctions Periodic, And Are We Due For One?

“If we start looking at the craters we find on Earth and the geological composition of the sedimentary rock, however, the idea falls apart completely. Of all the impacts that occur on Earth, less than one quarter of them come from objects originating from the Oort cloud. Even worse, of the boundaries between geological timescales (Triassic/Jurassic, Jurassic/Cretaceous, or the Cretaceous/Paleogene boundary), and the geological records that correspond to extinction events, only the event from 65 million years ago shows the characteristic ash-and-dust layer that we associate with a major impact.”

65 million years ago, a catastrophic impact from outer space caused the last great mass extinction on Earth, destroying 30% of the species that lived on our world at the time. These mass extinction events happened many times in Earth’s past, and the Solar System also passes through denser stellar regions of space periodically, as determined by the orbit of the Sun and stars in the Milky Way. It’s a combination of facts that might make you wonder whether the extinction events are also periodic, and if so, whether periodic impacts are predictable. If so, then shouldn’t we be aware of whether we’re living in a time of increased risk, and prepare ourselves for that possibility accordingly? After all, the dinosaurs didn’t have a space program or the capability of deflecting a dangerous object like the one that wiped them out.

But before we go that route, we should take a good look at what the data shows. Are mass extinctions periodic? Are we due? Let’s find out!