The Earth's dance partner

Ever heard of 3753 Cruithne?

I hadn't, which is surprising considering my obsession with astronomy.  It's an asteroid which is in a 1:1 orbital resonance with Earth -- in simpler terms, it is co-orbital.  It's sometimes been called "Earth's second moon," which is inaccurate because it doesn't orbit the Earth; in fact, its actual orbit is highly elliptical.  At its perigee, 3753 Cruithne is near the orbit of Mercury, and is outside the orbit of Mars at its apogee.

[Nota bene: the name "Cruithne" is from Gaelic, and because of the strange letter-to-phoneme correspondence in the Gaelic language, is pronounced "kroo-in-ya."  It's the name of an obscure king of the ancient Picts; its discoverer, astronomer Duncan Waldron, is Scottish, which probably explains the choice.]

Orbital resonance is one restricted solution to the more general three-body problem, which has yet to be solved by physicists.  The orbital interactions between two objects is thoroughly understood; add a third, and suddenly the math kind of blows up in your face.  You can run computer simulations starting with three objects of specific masses and velocities and see what happens, but a general set of equations governing any three (or more) body system has proven to be impossibly complex.  It's known that a few starting points generate stable orbits (resonance being one of those), and lots more of them prove unstable and eventually result in the objects colliding or flying apart, but trying to come up with the overarching mathematical scheme is currently out of reach.

3753 Cruithne's orbit, at least from our vantage point here on Earth, is a strange one.  If you were out in space, looking down on the Solar System, it wouldn't seem odd; an ellipse, tilted at a little less than twenty degrees away from the orbital plane of Earth:

[Image licensed under the Creative Commons Derivative work: User:Jecowa, Orbits of Cruithne and Earth, CC BY-SA 3.0]

But because of the weird perspective of being in a non-inertial (accelerated) reference frame, what we see on Earth is quite different.  As we watch 3753 Cruithne, it appears to be traveling in a bean-shaped orbit, first approaching us and then backing away as if we'd said something inappropriate:

[Image licensed under the Creative Commons User:Jecowa, Horseshoe orbit of Cruithne from the perspective of Earth, CC BY-SA 3.0]

Makes me realize how hard it is to come up with any reasonable model of moving objects in non-inertial reference frames.  Looking at 3753 Cruithne's strange wanderings almost leaves me sympathetic with Ptolemy and his nested epicycles.  (Isaac Newton, who understood the problem better than just about anyone else, wasn't nearly so forgiving, and called Ptolemy "an outrageous fraud.")

Its orbit classifies it as an Aten asteroid, a group of asteroids whose orbits cross that of the Earth.  For those of you who are of an apocalyptic bent, however, no need to lose sleep over 3753 Cruithne; its orbital tilt makes it no threat.  Its position has been run forward by computer models for thousands of years, and it has a zero chance of striking Earth.

That's assuming the orbital resonance remains stable, of course, and there's no guarantee it will.  There are other players in this gravitational game of pinball besides the Earth and the Sun; Venus and Mercury also come close to 3753 Cruithne on occasion, and a near pass could give the asteroid enough of a gravitational tug to destroy the resonance and destabilize the orbit.  The great likelihood if this happens, though, is it falling into the Sun or being flung out of the Solar System entirely; the chance of some gravitational slingshot effect propelling it into the Earth is about as close to zero as you can calculate.

So that's today's astronomical oddity that I, at least, had never heard of.  An asteroid in an ongoing celestial dance with the Earth.  Just goes to show that to find strange new stuff out in space, you don't need to peer out at the far reaches of the universe -- there's enough right here near home to keep the astronomers busy for a long while.

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Violent moon

If I had to vote for the single weirdest place in the Solar System, my choice would be Jupiter's moon Io.

Io is the innermost and third-largest of the "Galilean moons" of Jupiter, the ones that caused so much trouble for poor Galileo Galilei when he observed them in 1610 and informed the Catholic Church powers-that-be that we aren't the center of the universe.  It wasn't until the Voyager flybys in the late 1970s that we could see it as anything more than a fuzzy dot, even in the largest telescopes; the first close-up photographs invited comparisons to a moldy pizza,  Detailed photos from the Galileo probe in 1999 confirmed the original assessment: Io is one bizarre place.

1999 photograph of Io from the Galileo probe [Image is in the Public Domain courtesy of NASA/JPL]

The first weird thing about it is that it is the most tectonically active place in the Solar System.  Those pock-marks on the surface aren't impact craters, they're volcanoes.  In general, the smaller a body is, the less tectonically-active you might expect it to be.  Tectonic activity is (usually) triggered by convective fluid motion in a molten mantle or core, which requires a very hot interior to keep it going.  The heat comes from two sources; the energy released by its coalescence during its formation, and the decay of radioactive elements in its interior.  If that heat radiates away faster than it's being released, eventually the body cools off and freezes, and (most) tectonic activity stops.  Heat dissipates more rapidly from a small object, so they tend to shut down much sooner.  (That's what happened to the Moon, for example.)

But despite Io's small size, something is keeping it hot enough to create hundreds of active volcanoes.  But what?

It turns out it's the proximity to Jupiter.  The giant planet's gravitational pull creates significant tidal forces, and the stretching and compressing Io experiences generates enough friction in the moon's interior to keep the insides molten.  The result: violent volcanic activity that spews liquid sulfur jets into the sky, creating plumes as much as five hundred kilometers in height.  (It's the sulfur that's responsible for Io's bright colors.)

In fact, Io actually ejects so much material from its volcanoes that it has created a plasma torus around Jupiter in its wake -- a donut-shaped ring of charged particles tracing out its orbit.

Another cool thing about Io is that it's in orbital resonance with two of the other Galilean moons, Europa and Ganymede.  Io is the innermost, and has an orbital period exactly twice as fast as Europa and four times as fast as Ganymede -- a stable configuration that has since been found in other systems with multiple moons.  So every fourth revolution of Io, all three line up perfectly!

The reason this comes up is a new study out of Caltech that has found data suggesting an enormous underground magma ocean inside Io -- planetary scientists David Stevenson and Yoshinori Miyazaki believe the presence of a hundred-kilometer-thick liquid mantle explains the extremely active surface and its anomalous magnetic field, another feature Io shares with few other small bodies in the Solar System.

What lies deeper than the mantle is unknown.  Some astrophysicists believe it has a metallic core, but that question is far from settled.

What's certain is that Io is a peculiar place -- sulfur volcanoes, seething lava lakes on the surface, continuous "moonquakes" caused by the tidal forces exerted by the enormous planet Jupiter looming overhead.  And like anything odd and unexpected, it will continue to attract the attention of scientists, and we will continue to be astonished at what we learn about one of the weirdest places in our neighborhood.

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Moonstruck

A lot of times, it's the simple, easily-stated questions that are the hardest to answer.

Take, for example, the question of how the Moon formed.  Satellites around planets are common -- Jupiter has 79, for example -- but our own is a bit of an anomaly.  For example, if you make a list of moons in the Solar System in order of mass with respect to its host planet, the Earth's Moon is way out in front.  Its mass is 0.0123 of the Earth's.  Next in line would be Titan, which has a moon mass to planet mass ratio fifty times smaller (0.000237).

It's easy to picture a planet the size of Jupiter or Saturn gravitationally capturing blobs of the coalescing matter during the Solar System's formation, but it's harder to see a small planet like the Earth having the gravitational oomph to snag something the size of the Moon.  Another oddity is that of the sixteen most massive moons in the Solar System, the Moon's orbit around the Earth is by far the most eccentric.  Eccentricity is a number between zero and one that indicates how elliptical an orbit is, with 0.000 eccentricity being a perfect circle.  The Moon's deviation from a circular orbit is twice the next contender (which is once again Titan; whether that's a coincidence or not isn't known).  But the elliptical nature of the Moon's orbit is why its apparent size from Earth fluctuates, and explains why when there's a solar eclipse, sometimes it's total (complete coverage of the Sun's disk) and sometimes it's annular (occurs when the Moon is farther away and has a smaller apparent size, so at totality there's a ring of the Sun's disk still visible).

A third peculiarity of the Moon only became apparent when scientists got their first views of the far-Earth side around 1960, and they discovered that the far side had few maria -- the darker regions that were named for the Latin word for sea because it was thought early on that they might be water-filled oceans.  The largest two, the Oceanus Procellarum (Ocean of Storms) and the Mare Imbrium (Sea of Showers) together cover about 10% of the near-side disk of the Moon, and given that they're dotted with impact craters they seem to be very old structures.  (The first Apollo manned landing, in 1969 in the Mare Tranquillitatis (Sea of Tranquility), showed that the darkness of the maria is due to their being made largely of the dark volcanic rock basalt.)

[Image is licensed under the Creative Commons Gregory H. Revera, FullMoon2010, CC BY-SA 3.0]

So something odd is going on here, but a research team headed by geophysicist Stephen Elardo of the University of Florida has come up with a compelling answer to at least one piece of it.  The best hypothesis for the formation of the Moon, the researchers say, is the head-on collision of two protoplanets, one about ten times larger than the other (the smaller is estimated to be about the size of Mars).

Wouldn't that have been something to see?  From a safe distance?

In any case, this colossal collision blew both planets to smithereens, creating a whirling cloud of white-hot rocks and dust.  When the debris cooled and re-coalesced, the heavier one (eventually the Earth) had a high enough gravity to sort out the mess and pull the denser elements, like nickel and iron, into the core.  The lighter one (eventually the Moon) didn't, so it was left asymmetrical, with one side enriched in uranium, thorium, and the elements collectively called KREEP (potassium [symbol K], the Rare Earth Elements [such as cerium, lanthanum, dysprosium, and yttrium], and phosphorus [symbol P]).  This combo is what created the maria.  Uranium and thorium are radioactive, and as they decay, they release heat.  One effect of rocks being enriched in KREEP elements is that it lowers their melting point.  This meant that the surface remained liquid much longer -- becoming the flat, dark basalt plains we now can see from Earth.  The other side, being much lower in uranium, thorium, and KREEP, froze solid very early, and the landscape largely lacks maria.

"Because of the relative lack of erosion processes, the Moon's surface records geological events from the Solar System's early history," said study co-author Matthieu Laneuville, geophysicist at the Tokyo Institute of Technology, in an interview with ScienceDaily.   "In particular, regions on the Moon's near side have concentrations of radioactive elements like uranium and thorium unlike anywhere else on the Moon.  Understanding the origin of these local uranium and thorium enrichments can help explain the early stages of the Moon's formation and, as a consequence, conditions on the early Earth."

So that's one piece of the puzzle.  It brings up other questions, though, such as whether the fact that all this happened on the near-Earth side is a coincidence or was driven by something about the collision that formed the Earth-Moon system.  But whatever the answer to that is, the whole topic is fascinating -- and the violence of our satellite's origin is something to remember the next time you're looking up on a clear, peaceful moonlit night.

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This week's Skeptophilia book recommendation of the week is for anyone who likes quick, incisive takes on scientific topics: When Einstein Walked with Gödel: Excursions to the Edge of Thought by the talented science writer Jim Holt.

When Einstein Walked with Gödel is a series of essays that explores some of the deepest and most perplexing topics humanity has ever investigated -- the nature of time, the implications of relativity, string theory, and quantum mechanics, the perception of beauty in mathematics, and the ultimate fate of the universe.  Holt's lucid style brings these difficult ideas to the layperson without blunting their scientific rigor, and you'll come away with a perspective on the bizarre and mind-boggling farthest reaches of science.  Along the way you'll meet some of the key players in this ongoing effort -- the brilliant, eccentric, and fascinating scientists themselves.

It's a wonderful read, and anyone who is an aficionado of the sciences shouldn't miss it.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Bridging the Great Divide

One of the main things that separates scientists from the rest of us is that they notice things we would just take for granted.

Gregor Mendel started in the research that eventually would uncover the four fundamental laws of inheritance when he noticed that some traits in pea plants seemed to skip a generation.  Percy Spencer was messing around with vacuum tubes, and noticed that in a certain configuration, they caused a chocolate bar in his pocket to melt -- further inquiry led to the invention of the microwave oven.  French physicist Henri Becquerel discovered radioactivity when he accidentally ruined some photographic plates with what turned out to be a chunk of uranium ore.  Alexander Fleming saved countless lives with the discovery of penicillin -- found because he wondered why a colony of mold on one of his culture plates seemed to be killing the bacteria near it.

I consider myself at least a little above average, savvy-wise, but I don't have that ability -- to look at the world and think, "Hmm, I wonder why that happened?"  Mostly I just assume "that's the way it is" and don't consider it much further, a characteristic I suspect I share with a lot of people.  So here's some recent research about something I've known about since I first started reading junior books on astronomy, when I was maybe ten years old, and never thought was odd -- or even worth giving any thought to.

There's a strange gap, something astronomers call "The Great Divide," between Mars and Jupiter.  The distance between Mars and Jupiter is over twice as great as the diameter of the entire inner Solar System.  In that gap is a narrow band called the Asteroid Belt -- and not a hell of a lot else.

Even more peculiar, when you think about it (which as I said, I didn't), is why inside of the Great Divide all the planets are small, dense, and rocky, and outside of it the planets are low-density gas giants (I do remember being shocked by the density thing as a kid, when I read that Saturn's overall density is lower than that of water -- so if you had a swimming pool big enough, Saturn would float).

[Image is in the Public Domain courtesy of NASA/JPL]

The problem with these sorts of observations, though -- even if you stop to wonder about them -- is that until very recently, we pretty much had a sample size of one Solar System to work with, so there was no way to tell if any particular feature of ours was odd or commonplace.  Even now, with the discovery of so many exoplanets that it's estimated there are a billion in our galaxy alone, we only have tentative information about the arrangement of planets around stars, to determine if there's any sort of pattern there, such as the apparent one in our neck of the woods.

Well, it looks like the physicists may have explained the Great Divide and the compositional difference of the planets on either side of it in one fell swoop.  A team from the Tokyo Institute of Technology and Colorado University have found that the Great Divide may be a relic of a ring of material that formed around the early Sun, and then was pulled apart and essentially "sorted" by the gravitational pulls of the coalescing planets.

The authors write:

We propose... that the dichotomy was caused by a pressure maximum in the disk near Jupiter’s location...  One or multiple such—potentially mobile—long-lived pressure maxima almost completely prevented pebbles from the Jovian region reaching the terrestrial zone, maintaining a compositional partition between the two regions.  We thus suggest that our young Solar System’s protoplanetary disk developed at least one and probably multiple rings, which potentially triggered the formation of the giant planets.

And once the process started, it accelerated, pulling dense, rocky material inward and lightweight, organic-chemical-rich material outward, resulting in a gap -- and an outer Solar System with gas giants surrounding an inner Solar System with small, terrestrial worlds.

"Young stellar systems were often surrounded by disks of gas and dust," said Stephen Mojzsis of Colorado University, who co-authored the paper, which appeared in Nature three weeks ago.  "If a similar ring existed in our own solar system billions of years ago, it could theoretically be responsible for the Great Divide, because such a ring would create alternating bands of high- and low-pressure gas and dust.  Those bands, in turn, might pull the solar system's earliest building blocks into several distinct sinks -- one that would have given rise to Jupiter and Saturn, and another Earth and Mars.

"It is analogous to the way the Continental Divide in the Rocky Mountains causes water to drain one way or another.  That's similar to how this pressure bump would have divided material in the early Solar System...  But that barrier in space was not perfect.  Some outer Solar System material still climbed across the divide.  And those fugitives could have been important for the evolution of our own world...  Those materials that might go to the Earth would be those volatile, carbon-rich materials.  And that gives you water.  It gives you organics."

And ultimately, it gives the Earth life.

So here we have a strange observation that most of us probably shrugged about (if we noticed it at all) that not only was instrumental to the formation of our own Solar System, but might (1) drive the arrangement of planets in star systems everywhere in the universe, and (2) has implications for the origin of life on our own -- and probably other -- worlds.

All of which brings to mind the wonderful quote by Hungarian biochemist Albert von Szent-Györgyi -- "Discovery consists of seeing what everyone has seen, and thinking what nobody has thought."

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This week's Skeptophilia book of the week is a dark one, but absolutely gripping: the brilliant novelist Haruki Murakami's Underground: The Tokyo Gas Attack and the Japanese Psyche.

Most of you probably know about the sarin attack in the subways of Tokyo in 1995, perpetrated by members of the Aum Shinrikyo cult under the leadership of Shoko Asahara.  Asahara, acting through five Aum members, set off nerve gas containers during rush hour, killing fifty people outright and injuring over a thousand others.  All six of them were hanged in 2018 for the crimes, along with a seventh who acted as a getaway driver.

Murakami does an amazing job in recounting the events leading up to the attack, and getting into the psyches of the perpetrators.  Amazingly, most of them were from completely ordinary backgrounds and had no criminal records at all, nor any other signs of the horrors they had planned.  Murakami interviewed commuters who were injured by the poison and also a number of first responders, and draws a grim but fascinating picture of one of the darkest days in Japanese history.

You won't be able to put it down.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Postcards from deep space

It's way too easy to let yourself get caught up in all the ugliness in the news.

Scandals, allegations of crimes of all sorts by various public figures, humanitarian crises, ecological damage done by people who seem to have no real care for the long-term habitability of the Earth.  Hypocrisy, dishonesty, corruption.

Pretty dark stuff, and to judge by the news, it's about all humanity has to offer.

So today I'm going to write about something hopeful -- an indication that we have the capacity for a whole lot of positive things.  Curiosity, innovation, teamwork, and a deep-seated determination to understand the universe we live in.

Ultima Thule is the popular (but unofficial) designation of the object that is, much more prosaically, called MU-69.  It's far out in space by anyone's standards, circling the Sun at an average distance of 44 AU (astronomical units, the average distance from the Earth to the Sun).  By comparison, Neptune -- the outermost actual planet -- orbits at about 30 AU.  Even Pluto (which was downgraded from "planet" to "dwarf planet" status a few years back) orbits at an average 39.5 AU.

So if you reached Pluto, you'd still have a distance of four times the Earth to the Sun to cover before you'd be within hailing distance of Ultima Thule.

And it's not a large object, making me wonder how the hell anyone saw it in the first place.  It's highly oblong, with a long axis of about 33 kilometers and a short axis of 19 kilometers.  So that's the first amazing thing; using the Hubble Space Telescope, we spotted an object only a little more than twice the size of Manhattan Island from a distance of 6.5 trillion kilometers.

Then, astronomers decided it'd be a good place to visit, based on its position with respect to the trajectory of the New Horizons probe, which had sent back stunning photographs of Pluto in 2015.  So off the little spacecraft went, to visit one of the most distant objects known in the Solar System.

The photographs coming back are amazing.  It was known that Ultima Thule was oddly shaped, but as the probe approached, it became clearer and clearer that it was just an oval.  Some of the earliest photographs made it look like a spinning bowling pin.  When it got closer, we were able to see that it was shaped more like a snowman, leading to the inference that it was formed by the collision of two roughly-spherical bodies.  The impact must have been remarkably gentle; too fast, and it would have shattered one or both of the objects.  Instead, they appear to have spiraled in toward one another until finally they kissed -- and stuck together.

[Image courtesy of NASA/JPL]

Astronomers are understandably thrilled by this opportunity to study an object close-up that is observable only as a 26th-magnitude speck of light from our position here on Earth.  Astrophysicist and former member of Queen Brian May wrote a song for the occasion, called "New Horizons," celebrating our perpetual drive for extending what we know about the universe.  (This isn't the first time May has worked his scientific background into his music.  One of Queen's best, and most under-appreciated, songs is the bittersweet and poignant "'39," which has as its basis the bizarre effects of near-lightspeed travel -- especially time dilation, which describes how fast travel slows down the passage of time, so that if you were to leave behind your loved ones and travel near the speed of light, you'd age only a year while the loved ones you left behind would age decades.  If you haven't heard it, click the link -- it's fantastic.)

NASA has promised better photographs as more data comes streaming in from the probe, but the ones they've already gotten are pretty amazing.  When you're looking at them, keep in mind that you're looking at something out there spinning space, half again as far from the Sun as the planet Neptune, and be amazed.

So let's take a break from the constant stream of negativity and vitriol, and consider what incredible journeys we can take into wonderment and beauty, journeys that have taken us into the farthest reaches of the Solar System and beyond.  As we sit down here, engaged in our petty squabbles and petty rhetoric, an intrepid little probe is out there relaying back information about are on the very edges of what we know.  And that, I think, is something about which humanity should rightly be proud.

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Carl Zimmer has been a science writer for a long time, and his contributions -- mostly on the topic of evolution -- have been featured in National Geographic, Discover, and The New York Times, not to mention appearances on Fresh Air, This American Life, and Radiolab.  He's the author of this week's Skeptophilia book recommendation, which is about the connections between genetics, behavior, and human evolution -- She Has Her Mother's Laugh: The Powers, Perversions, and Potentials of Heredity.

Zimmer's lucid, eloquent style makes this book accessible to the layperson, and he not only looks at the science of genetics but its impact on society -- such as our current infatuation with personal DNA tests such as the ones offered by 23 & Me and Ancestry.  It's a brilliant read, and one in which you'll learn not only about our deep connection to our ancestry, but where humanity might be headed.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Orange dwarf catastrophe

It's no great insight that the media likes sensationalized stories, and that a lot of them (including, sadly, some major news outlets) have the attitude that facts don't matter much as long as they can keep readers reading.

What is more frustrating is the way the readers themselves become complicit in this dissemination of bullshit.  Now that we have the interwebz, sending along ridiculous "news" stories takes only a click. And before you know it, you have people believing that humanity is going to be wiped out because the Solar System is going to be destroyed during a collision with an orange dwarf star.

The original study, by astronomer Coryn Bailer-Jones of the Max Planck Institute for Astronomy in Heidelberg, is interesting enough.  Astronomers have long known that the stars move relative to each other; this means that the constellations aren't fixed, and that millions of years from now, a time traveler from today wouldn't recognize any of the current star patterns.  (I still remember my first encounter with this idea, on Carl Sagan's Cosmos, when I was a freshman in college.  Seeing the animation of the movements of the stars in the Big Dipper was one of those moments when I realized, "I really want to know more about science!")

So it's not too surprising that some stars will get closer to the Sun over time.  And Bailer-Jones found that two orange dwarf stars are predicted to make relatively close approaches -- HIP 85605 could get as close as 0.13 light years, and GL 710 could make a pass of 0.32 light years.

[image courtesy of the Wikimedia Commons]

Cool stuff.  But the media, unfortunately, is not content simply to report the facts.  Because that, somehow, would be boring.  This research has been picked up by a number of different online news sources, and one and all, they focus on the fact that this "close pass" might wipe us all out by gravitationally dislodging comets from the Oort Cloud, resulting in a "rain of comets," some of which could, perhaps, collide with the Earth.

Notice how many times I said "could" and "might" in the previous two paragraphs?  Bailer-Jones is up front about her study being speculative; the upper bounds for the pass distance of the two stars are 0.65 light years and 1.44 light years, respectively.  To put things in perspective; the closest estimate of HIP 85605 to the Sun was 0.13 light years, right?  Well, Pluto is 13 light hours from the Sun.  So this means that even at its closest, HIP 85605 will be 9,000 times further away than Pluto.

Next, let's consider the likelihood of a disruption of comets leading to a "rain of comets" and the certainty of a devastating Earth strike.  Let's assume that we do have a bunch of comets swooping inwards from the near pass of these stars.  What kind of target does Earth represent?

The issue here is scale, of course, and the amount of the Solar System that is (virtually) empty space. The best analogy I have run across is that if you shrank the entire Solar System down to a circle with a radius of 1,000 meters, with the orbit of Pluto as its perimeter, then the Earth would be about 7 meters from the center.

And it would be the size of a peppercorn.

So it's not exactly a huge target.  Yes, a comet or two could strike the Earth, as they have repeatedly during Earth's history.  No, it would not cause a rain of death.

But those aren't the only misrepresentations in the "news" story.  Not only has Bailer-Jones's research been sensationalized, it's had information added to it that is outright false.  In the above-linked story, which is no worse than the various other versions I've seen (i.e., I didn't pick this one because it was especially bad; they were all bad), here are some direct quotes, with commentary:

Apparently, the comets are made of rocks, dust and organic materials.

Actually, comets are mostly ice, a fact which has been known for decades and would have been immediately apparent had the author bothered to consult Wikipedia.

(T)he gravity [of the stars] can attract comets into the inner solar system and the passing comets might harshly affect Earth's atmosphere due to the powerful ultraviolet radiation that the comets might cause.

Ultraviolet radiation from what source, pray?  Comets aren't giant orbiting tanning lamps, for fuck's sake.

(A) small number of the alleged stars might explode like supernova while passing through the Oort Cloud.

Oh noes!  Not alleged stars explode like supernova!  That sound bad!

The Hip 85605 might reach the solar system in 0.13 to 0.65 light years away, while the GL 710 might take around 0.32 to 1.44 light years.

Ninth graders in Earth Science learn that a light year is a measure of distance, not time, a point that seems to have escaped the author, making me wonder how he ever got chosen to write a science story.  To be fair, unit confusion also plagued the writers of Star Wars, wherein we famously had Han Solo boasting that the Millennium Falcon had done the Kessel Run in "less than twelve parsecs," which would be like saying that your car was so fast that you went to the grocery store in less than five miles.  (Of course, there are Star Wars apologists who have talked themselves into thinking that the scriptwriters had some kind of fancy time-travel space-warp relativity thing in mind when they wrote it.  Myself, I think they just didn't know what a parsec is.)

And of course, it's only midway through the article that we find out when this catastrophe is predicted to happen:

1.3 million years from now.

So, to boil it all down:

Two small stars might, or might not, pass 9,000 times further away from the Sun than Pluto is, some millions of years in the future.  This could increase the number of comets entering the inner Solar System, generating a somewhat higher likelihood of a comet striking Earth.

But that version of the story wouldn't have induced so many people to read it and pass it along, would it?  Nope.  So they add sensationalized nonsense to it, so as to make it better clickbait.

At least it's still better than the post I saw on social media yesterday, wherein someone asked for help for a school project their child is doing regarding why the stars were created.  The responses included that god had made them "to rule the night with the moon," "to be for signs, and for seasons, and for days, and years," and "to declare god's glory."  The scholarly references given were the Book of Genesis and Psalm 19.

But hey, if you're going to buy into non-science, I guess you should go all the way, right?