A Comet! This one's for real

Hinzugefügt: 2026-05-05

[00:00:00]Well, hello.

[00:00:02]Uh, little over a week ago, I told you about the great comet of 2026 that was going to be so bright it was visible in the daytime and would be one of the most spectacular comets ever seen as we see it next to the sun in broad daylight.

[00:00:17]And truth is at the right time I was looking but I did not know that comet C/2026A1 maps had already disintegrated and never made it to parhelion.

[00:00:33]This often happens to small comets especially the crit sungrazers or other sungrazing comets. They get so close to the sun that either the solar wind or the gravitational effects or both just pulverize it and there's nothing goes around the sun but a cloud of dust and gas. So it didn't happen but it was worth looking just in case. However, hope is not lost because as I speak there is a comet which has reached naked eye visibility in the morning sky. This is comet C/2025R3 pan stars and it is looking promising. I have not seen it yet. I'm going to get up in the morning early before twilight and see if I can spot it. It has reached a magnitude of 4.6 which is under good dark skies an easy naked eye object. The magnitude of an object is the measure of its brightness and it uses a logarithmic scale that gets brighter as the numbers get lower. So the brightest stars in the sky excluding the very brightest such as Sirius and Kenopus are around zero magnitude. The faintest stars in the sky visible to the naked eye under good conditions are magnitude six. So zero is very bright, six is barely visible, and 4.6 is respectable. It should be quite visible out there in the morning sky. In fact, I'm even optimistic that I might be able to see a bit of a tail, maybe even more than just a bit of a tail. So, let me explain really quickly what comets are. The quickest explanation is these are just chunks of ice and dust.

[00:02:21]Uh sometimes they're referred to as dirty snowballs. Maybe maybe a snowy dirt ball is a better name for it. But these are objects that tend to come from far out in the solar system or further mostly water ice or methane ice and a lot of dust. So as these approach the sun, the solar wind starts to vaporize some of this ice and knock off some of this dust and that trails behind the comet forming a tail. So, if we have an comet that's kind of far away, they tend to look in a telescope. I'm going to try to draw one. Well, it depends on how far away it is. If they're very far away with the tail pointing away from the sun, you might see nothing but a concentration of light that looks sort of star-like with a fuzzy area around it. And I'm deliberately drawing that pretty small. I'll draw something just a little bigger. Just a, you know, a concentration where the nucleus is. and a lot of the concentration of dust and gas and just a halo around it. But as they approach the sun, you will start seeing a little bit of a tail. They tend to be kind of spiky looking as they're far away. And as they get closer, that tail gets longer and a little broader.

[00:03:35]And eventually as it approaches the sun, we get the classic look of a comet. Let me go ahead and erase this.

[00:03:45]the classic look of a comet which might be something like this where we have a sweeping tail and a bright nucleus somewhere around there.

[00:03:55]And so the sun is always in that direction because the solar wind is what's blowing this dust and ice away from the comet. And I've drawn the dust tail here. And a lot of comets have a dual tail where they'll have a smaller tail directly away from the sun. So the sun would be in that direction. And so this tail here called the ion tail, which is mostly ionized gas, is going to go directly away from the sun. But the dust tail is going to be sweeping. And it depends on the geometry in which way it's going to sweep. Now looking at this you would say well the comet must be moving in this direction but not necessarily. It could be moving in either direction because it's not only the direction of movement that causes the direction of the sweeping dust tail but also the direction we are looking at it. And once in a while we have comets with anti. So what is that? Well let's say we have a comet that's fairly close to the sun.

[00:05:04]Therefore, it's going fairly fast coming close to parihelium, which is the closest approach to the sun. So, we might have comets that look something like there's the tail, and it's very, very wide. And once again, there's the bright nucleus.

[00:05:19]Probably really can't see what I'm drawing there. I'll just draw this a little bigger here. There's the the tail of the comet. The coma is the part around the nucleus. And then the nucleus. Probably should draw that a little closer to here. Now, I'll zoom in on that hair so you can see what the idea I have. And here's a picture of a comet. Um, I don't know what picture I'm going to put up there yet, so I'll just put the name down below. And so, let's say we have a tail that's sweeping like this.

[00:05:46]And if we are at the Earth over in this direction, so somewhere over here is the Earth and we're looking at that, we're going to see a tail here and a tail there. And so when we look straight at it, we're going to see something more like there's the nucleus and there's the tail.

[00:06:08]And since we're looking straight on, we don't see any curving. And that tail curves back and gets thinner and we see a little spike sticking ahead of the main uh nucleus there. So sometimes we have a tail and an anti-tail.

[00:06:23]And so it's just some interesting things you might see when a comet gets bright enough to see naked eye. So what are these? So once again, they're basically dirty snowballs. They tend to come from an area called the Orort cloud, which is discovered by an astronomer named Orort.

[00:06:41]And really discovered is not the right name. He guessed that there must be a cloud because of the nature of comet orbits. He calculated the orbits of many comets. And if we take a quick look at a drawing of the solar system, we have the sun here in the middle.

[00:07:01]And I'll draw planets on a plane. So here's I'll just draw a dotted line for the ecliptic plane, which is where the planets live. So we have in our solar system, we have Mercury and then they might be anywhere along there. I'll just draw them on the same side though.

[00:07:17]Venus, Earth, Mars, and way out there, Jupiter. But of course, they could be anywhere along that line. I'm just drawing them all in one side. And if we zoom away, let's draw this zoomed far away. We have the sun. Just a little dot here. I'll make it a little bigger so you can see it on the screen. And then we have the ecliptic plane. I'm drawing it at an angle because I can.

[00:07:46]And most objects in the solar system are going to be found along this ecliptic plane. Most of the planets and we have the Kyper belt which is a area of big chunks of ice mostly which is where that uh object called Aerys lives and a few other large objects. In fact, Pluto is part of the Kyper belt. And so these are objects that are in a basically a donut just beyond Neptune. But what Orort noticed is that when a comet comes to the sun for the first time, let me qualify that real quickly. We have comets that are in this part of the solar system. Most famous example of course is Hal's comet which goes out a little beyond uh Uranus I believe. Don't know exactly how far it goes around Uranus or Neptune. goes pretty far out there and comes in every 76 years and it's in a highly elliptical orbit. So I'll just draw a very terrible ellipse and goes around every 76 years. But it is close to the plane of the ecliptic because the reason it comes so often is because it came in by chance came in along the ecliptic passed close to Jupiter. Jupiter grabbed it and caused it to go into a closer orbit that comes every 76 years or so.

[00:09:13]But typically a comet has a much longer orbit. So what Ort noticed is that comets that tend to come from other directions, let's say here's a comet here and on back out, they tend to go out very far and have very long periods.

[00:09:30]And he noticed when he calculated the orbit that they tended to have an apphelion, the most distant place from the sun at about the same distance. So another comet comes in at random from this distance around the sun. He calculated the orbit and it comes from about there. Another one comes in from about this direction around the sun back out and about the same distance. But Orton noticed that comets that appear to be coming in for the first time and have not been captured and put into shorter orbits tended to have their apphelons at about the same distance but in a spherical shape. So he postulated there must be a number of objects out here in addition to comets that are orbiting very very far from the sun. We're talking about 2,000 to 5,000 astronomical units. And what's an astronomical unit? Well, it's a astronomical number. It's the distance that the Earth orbits from the Sun. So, we're talking about 93 million miles.

[00:10:37]And I forgot what that is in kilometers, but there it is. So, talking about thousands of astronomical units to where these comets are, and these orbits take thousands of years. So he said there must be something out there and every once in a while a passing star or something or maybe just two objects coming close to each other change the orbit enough that something was orbiting out here and something disturbs it. He says a like a passing star causes its orbit to go something like that and change it. So that's the speculation about where comets come from. bunch of chunks of dirty ice out there floating around thousands of astronomical units away and once in a while something causes one of them to lose energy and come in and go by the sun.

[00:11:36]And that last comet that was hopefully going really close to the sun a week or so ago was a CO sungrazer. And the theory about that is that this uh comet came in around 300 BC and as it passed by the sun it broke up into multiple pieces or two at least two big pieces and went way back. Well, we want to go back to the orc cloud. Don't want to go too far.

[00:12:04]That's a very terrible orbit. It should be almost a straight line in and out.

[00:12:09]But anyway, uh that broke up into multiple pieces and that pieces of that broke up into more pieces. And so now we have this cloud, if you will, of comets going some direction. I'm not being accurate as to which way this is, but basically a cloud of comets following almost the same orbit. And every few weeks or months, one of those comets comes by the sun. Most of them are very tiny and very few of them make it past the sun. But they come within a couple hundred thousand miles of the sun. So very very close to the sun and tend to disintegrate. But once in a while we get a big one like Ikei in 1965 that gets close enough to the sun that got bright enough to be seen in broad daylight next to the sun and it broke up into two or three pieces as it went out.

[00:13:00]So in a thousand years or so when Iekki returns it'll probably come one one year and another year another piece or whatever because it broke up and is being scattered along that orbital plane. So anyway that's what comets are and um they're out there all the time.

[00:13:18]In fact here's a chart from heavensabove.com which shows all of the comets now visible in small telescopes.

[00:13:26]And what are there 20 of them or so there? So, I could go out tonight with my telescope under dark skies and probably see several comets. Um, what will they look like? Um, little fuzzy spots in the sky, so they won't look too exciting. But once in a while, we get a comet that's big enough that comes close enough to the sun and closest and and close enough to the earth that it becomes bright enough to be a naked eye object and with any luck maybe a spectacular naked eye object. So now what we have out there in the morning at approximately magnitude 4.6 six. So, respectable naked eye brightness is comet C/2025 R3 pan stars and uh once again get up oh maybe an hour and a half or so before sunrise before the twilight starts and look out uh at my latitude it's uh going to be a little north of east so I have to get some place find a good eastern view and where I can see a little bit north of at least probably. How high is the horizon? I'm assuming it's going to be probably about that high. So maybe is that about 15 20 degrees above the horizon and just might see a fuzzy thing out there. Um tell you the truth, as bright as it is, I wouldn't be surprised. I'm optimistic that there will be some invisible tail to this comet. So anyway, um if you want to know more about what it's doing and a finder and a finder chart of how to see it across the sky, you can go to heavensabove.com and go make sure you get your uh location right in there.

[00:15:11]Might want to create a an account and uh look at the just go and go poke the comets and see the list of comets and see what uh our C/2025R3 panars is up to. and you poke that, it'll show you where it is. Right now, it's in the constellation Pegasus. So, it's in the great square. And um not much else to say about that. So, let's hope we can see that comet. And once again, I am building an astronomy class at Vocadam. I'm working on the chapter for the textbook on Tiko Bra, who was the last great astronomer before the invention of the telescope. And it's his very precise measurements that allowed Johannes Kepler to figure out how the planets orbit the sun. So, we'll be learning about that there. So, I hope you guys if you want to get up to see the comet, good luck. I don't know why they always seem to come in the morning, but there it is. And I will be out there and maybe we'll see something.