Let's Find Out - Drawing the first planet: Mercury | soft-spoken ASMR [science, space, astronomy, history]

Episode Date: May 5, 2019

Like many things in the solar system, Mercury has been observed by humans for thousands of years. It has a connection to our collective psyche (even if it's only what we have projected onto it), and a history of eluding those that try to understand it. It is the smallest and innermost planet in the Solar System, bearing the full brunt of the Sun's volatile coronal mass ejections. It's orbital eccentricities fooled astronomers and mathematicians for centuries and it has amazed current scientists with it's recently discovered water-ice and organic compounds. Let's find out all about this temperamental, inferior planet with a voluminous iron core.Thanks for watching. #ASMR #Mercury #space

So we had a fun time drawing the sun last time. I thought it might be a fun series to start drawing the planets one by one. So tonight it's going to be Mercury. Little research for this video, there's actually a ton of really interesting things about Mercury that I had no idea. It's, uh, to me, it was always kind of the most boring of all the planets. It's the smallest for one. So that's kind of a strike against it right away. Seems to have the least, you know, Venus has a thick atmosphere.

It's the hottest. Mars is the most like Earth, I guess. It's got the highest probability of a, place we might colonize, according to Elon Musk and many others. And then they get the gas giants, just have sheer enormity going for them. So I was pleasantly surprised and actually won over, definitely won over. I discovered all these interesting facts about Mercury. So let's touch upon the mythology, the history of our observations of Mercury.

And then we'll transition into the actual science and elaborate on what it is that we know all the way up to the current, most current probe, the messenger probe. Mercury is one of six planets. We can see with the naked eye, the others being Venus, Mars, Jupiter, Saturn. If you look outside, of course. All our distant ancestors probably didn't realize the planets were light years closer and millions smaller than all the other little holes to heaven they might have witnessed in the night sky.

They were no dummies. They really just hadn't separated their knowledge of how we should act from knowledge of how less complex objects in the world do act. That being the distinction between morality and values, the things we get from spiritual wisdom, and objective-based observations about phenomena. They hadn't developed technology to probe deep into the heavens, but they certainly observed how through the seasons,

you know, say we have a constellation or iridespout, there were certain points of light in the sky that wandered to all the same spot of the sky. Night after night for a certain duration throughout the year. But then you have a slightly brighter planet. This thing that really looks like a star to the naked eye, moving with respect to the background or fixed. Really betting that our ancestors, maybe a million. I really believe that they would have picked up on this and paid special attention to these wandering stars. You know, light pollution from the cities sadly drowned out the glory of the night sky from my sky.

most of us, but if we were to look at the area, it would be pretty obvious to us this movement of Mercury, Venus, Mars, especially in Jupiter and Saturn. You know, I always like to imagine what it might have been like that far back in time, in what kind of awe the stars looking up at night, you know, must have invoked in our ancestors, given that, you know, with all our knowledge, um, it's, it's really still almost overwhelming how, how amazing it is to look into the sky at night on a clear night and see these points of light that we know are, you know, hundreds or at least tens of thousands of light years away. We have a science. understanding, but to our ancestors, it must have been just a true mystery, you know, really what

it was that these things were. They're so intangible. They're so far off. They must have, um, they must have imbued them with a certain spiritual sacredness, undoubtedly. So we're going to go back maybe 10 millennia or so ago in the past briefly and experience a special moment for an ancient Mesopotamian astronomer. But first I want to do, I wanted to draw, give us a little outline of this area. Maybe we will do Africa here. Or to Israel, Eastern Mediterranean. Turkey, leading west into Greece. Greece is the little outcroped, the Peloponnesus, lower Peloponneses. Like the Adriatic, the Adriatic of Italy, Sicily. This perspective, maybe

Northern Europe vanishes over the horizon. Let's go ahead and bolden these lines real quick. And you guys might be wondering why I'm focusing on Earth if this is a video of about Mercury. And that's because Mercury got its name from the ancient Romans. Who got their God Mercury from Hermes?

Who is a traditions from the Near East in Egypt? Let's see. Red Sea here. Back to one of the oldest known civilizations we have over here between the rivers

that come from these mountains into the Persian Gulf Caspian Sea over here this civilization here is Mesopotamia and just something as simple as the name Mercury has such a deep history that I wanted to share it with you guys

so let's make sure to draw Cyprus Crete let's shade in the oceans real quick We have the Red Sea down here Persian Gulf

Caspian Sea No forget The Black Sea Up here Nile Delta Right there Just imagine this Just imagine we're

Up early Before the birds And the sun We grab a quick bite of bread And head out the door of our little hut into the darkness to the nearby

fertile banks of the Euphrates river make some little saw grasses right there yistar is which is Venus near the horizon

lighting bright which is Mars above it then ambling towards our destination we feel the soft crunch of dewy grass beneath our bare feet as we walk along the starlit shoreline, we breathe in the calm morning air, and as we walk,

we look directly up to gaze in awe at the glowing river of stars, called the Milky Way. Now standing out among these are the two greatest of the wandering stars, the ringed as Saturn of gods. We call Jupiter today, we see them beaming down a proving low. and we've arrived at our suitable outlook over the banks across the prairies facing east into the dark

we wait patiently but excitedly then gradually we see the paleolithic black starry night gives way to the first glow of dawn and with it sunrise and right before the sunrises we're going to see mercury

and there it is. So it's brilliant. Its sharp radiance is only slightly tarnished by the ambience of the coming sunrise. And just imagine beholding this, the swiftest, most ephemeral of planets, Nabu, which we call Mercury, as it convenes with the other for this ancient sky.

For just a brief hour before, the break-up day, the planets have aligned, and we've just witnessed an awesome phenomena that may not come again for another generation. And this is the emergence, the convening of all the stars in the night sky, all at once. And just imagine what that would have been like for some, no telescope, but maybe some rocks, some monolithic, some structures aligned so that he knows where to look in the night sky for these celestial beings. There's been something to be, although there's no firm evidence of the original discovery of the ancient, in the ancient texts of Mercury, the first mentions of it appear to be from around all the way back to 3,000 BC. that's 5,000 years ago by the Samarians

in this area here Mesopotamia which now is Zigeron the first official observations of the planet Mercury are found in something called

The Mole is something just used to refer to these ancient texts there were a set of tablets a compendium of astronomical and astrological, because they were infused at the time,

knowledge made by their descendants, the Assyrians and the Babylonians, Babylonians, rather. Assyrians were a real big empire, Babylon was, as far as I understand, along the Persian Gulf at the southern end of Mesopotamia there. In these tablets, Mercury is called the, jumping star, the jumping planet, no doubt due to its dramatically fast movement relative to the other planets. All of these, all five of these, they do move with respect to the more static, stationary, more predictable, more cyclical background of stars. But, you know, Jupiter and Saturn being the furthest away of all these, they move the slowest.

so they do proceed across the sky and they all do their loops. But Mercury is the closest to us, and it's the closest to the sun. And so it sips around the sun faster than any other planet, as we'll talk about in a little bit. But from Earth, from our vantage point, that also makes it the quickest to pop up and dip below the horizon. If you can imagine we have a little peak below the earth, the sun right here, just below the horizon. Mercury is the closest to the sun, so of course it stays the closest to the horizon.

Let's just bolten the earth real quick. They called it the jumping star for that reason because it's so, so quick, even relative to the other planets. the other planets. Now about 500 years later, by about 1,000 BC, Babylonian astronomers had identified Mercury with the God of wisdom.

The associations of wisdom are literature, poetry, and knowledge, in general, pre-scientific kind of knowledge. And this was the god Nabu. Now, Nabu was important because it's the home planet

of Padmei and the great great jar jar binks. Just Misa kidding there. Misa kidding. There, you guys know that. Actually, Nabu seriously is, it began as a minor deity in the Mesopotamian pantheon of gods.

It was just initially just a mere scribe to the great god of gods, their version of Zeus or Jupiter. But Nabu gradually ascended. the hierarchy of Mesopotamian gods until he was depicted in later Babylonian art, actually riding Marduk's protective dragon, at times even superseding the importance and prestige of Marduk himself. And this is no doubt a testament to the growing importance of the transmission of written knowledge.

back then. There was a... the increased worship of wisdom over power, sheer strength of Marduk was kind of a metaphor for the growing importance of relaying information

in its written form in the attainment of wisdom. And then moving another thousand years forward maybe around 500 BC or so. Nabu's cult had actually expanded

from this the crucible of civilizations on earth all the way down to Egypt west through Israel and planted its seeds kind of all around the eastern Mediterranean and the ancient world

so there's bits of that as we'll see all around in Egypt in the pyramids. There actually was a cult in Egypt worshipping Nabu for a little bit. In Israel, there's a lot of evidence

of Nabu's transmission in the Bible in Isaiah 46, verse 1, for instance. Nabu is transposed into Nibo, designating someone who lives or was of Babylonian heritage in the Israel vicinity. And this is also the root of the mighty biblical king, Nebuchadnezzar.

You might remember that's Morpheus's ship in the matrix. And so, you know, over thousands of years this, God, it didn't die away. He was just transposed. into different forms and different names. From the southeastern Mediterranean, moved northwest. Worship of Nibo and his associated planet, remember, was again shifted across the Aegean, now into Greece,

and he was to be fused with Apollo, the God representing poetry, reason, and knowledge. And you can see there's a little bit of an overlap, right? So we'll draw our little Parthenoth. We'll make it go over the horizon there. But because the ancient Greeks actually thought that Mercury was two planets, again being the jumping planet, it's moving so fast. They called it Apollo when it was visible in the morning sky.

And Hermes, the messenger of the gods, when it briefly popped up in the last rays of the setting sun. Hermes became associated with his half-brother Apollo when he stole Apollo's precious cattle one day. And upon being called out for his theft, he actually invented the stringed instrument known as the liar, L-Y-R-E. gifting it to Apollo as compensation for the theft. Then Apollo in return actually gave him a caduceus as a gesture of friendship.

And this is represented as... Ship this around now. This is represented as a staff with two snakes twirling around it. And this is the modern... Let's see if I can... I got plans for that spot. Let's see, we'll, uh, it's just drawn right here. The Caduceus.

And this is a gesture of friendship. It's an astrological symbol for Mercury. But it, uh, it wasn't until about the 4th century BC that ancient astronomers in Greece realized the two morning and evening stars were actually one in the same. And, uh, as Apollo was a... already linked to the sun. The Greeks eventually came to know the planet only

as exclusively as Hermes. The Romans after them then, because they were focused on more earthly pursuits, like expanding their empire, they simply maintained the status quo. And their version of Hermes was Mercury.

So, over here, we have. So in other cultures, um, as far as that goes, Mercury is well known as well. The ancient Chinese, they called it the hour star. The Hindus and Germanic peoples associated it with Wednesday, actually. Um, the, the idea of the week, as you can imagine, is actually very, very ancient. because if anything, the period of the moon is about every 28 days. So the idea of a seven-day week, cyclical week, has been around for a while. And the Hindus actually named it after Buddha. And the Germans, they named it after their god, Odin.

Even the Mayan civilization in Central America, they knew it as an owl, the bird, and it was also, interestingly enough, a messenger in the realm of gods. Their owl was a messenger to the underworld. So that about takes care of the history of Mercury, and it wasn't until after, but Christ, after the first millennium A.D. the dawning of it at least, that the first truly scientific speculations began to give us a deeper understanding of Mercury's nature, as opposed to the, I would say, primarily psychological projections onto it that we've so far discussed. AD 150, the Roman Egyptian astronomer Ptolemy, he wrote about the possibility of planetary transatlantic,

it's so now I'm gonna move over to this side of the page you know I actually didn't mention I didn't mention this but um this being earth of course and this being mercury they're actually to scale roughly

um so when we think of the size of our planet mercury is bigger than our moon our moon might be like that big but of course the sun here is certainly not to scale but Ptolemy

thought maybe maybe because we could see Mercury over here moving so fast he assumed correctly so that it was much closer to the sun than most other planets

but he was wise enough to know that it was so small relative to the sun that or at least so dim and small you probably wouldn't be able to see it and he was right without telescopes you certainly can't see it transit the sun

but his speculations were certainly planning the seeds for future science a thousand years after this so around you know 1100 or so the collapse European civilization the the petering out of the Roman Empire

from, you know, all the way to 2,300 AD, all the way to 7 or 800 AD, left a huge lapse in academic intellectual achievements in Europe. And thankfully, the Middle East, there were kind of a, I think it was called, the Islamic Golden Age, they actually were a wealth and a nexus of cutting-edge science and philosophies and ideas. You know, the word algebra is a root word of a famous Islamic mathematician.

And a lot of our words that we use today are derived from this era. So much of our ancient knowledge of even the Greeks, and Romans is only wisdom that we've been able to extract from the texts of the Muslims and Arabs around the Middle Ages that preserved, because there were such a huge trading hub, that they were able to preserve these texts. Around during the Crusades and afterwards, when we regained economic, relationships with the Middle East, we were able to extract the previously lost information of maths and philosophies and whatnot, great literature that we had lost in Europe.

So that's interesting that we have the Islamic Golden Age. There was an astronomer there, an Islamic astronomer in the Middle Ages, called Abu Ishok Ibrahim Al-Zakal that predated modern astronomy by he actually described Mercury's orbit as highly elliptical we have our little sun right here and maybe we'll make it bigger Al-Zakal or Al-Zakali rather

predated astronomy by recognizing that it it orbits the sun much much like the shape of I mean planets at that time if they were considered to orbit the sun they were assumed like all things in the celestial sphere to be perfectly circular to be perfect in all respects perfect spheres and perfectly have undergo circular because of course the cosmos was associated with divinity so they wouldn't accept anything

less than perfect geometric shapes so Alzacali was far ahead of his time for this so the closest point and the furthest point here Parahelian and this is called aphelian drastically different from all the other planets and then 200 years after that an Indian astronomer going over to India now

way over here over the horizon named Nilikanta Somayaji developed an interesting model of the solar system with Mercury orbiting the sun but the sun in his model was

still orbiting earth but nonetheless at least he got half got it half right you know because many of the planets back then again earth was the general philosophy of the cosmos was that earth was the center of everything so it was a geocentric model of the universe and this model was eerily similar to the famous tycho brahe the um i think danish astronomer a couple hundred years later but it was a good sea to be planted about mercury's orbit and then in the 1600s moving forward another couple hundred years galileo was then the first to see mercury through a telescope but his lenses of course weren't yet powerful enough to witness the the slight phases of Mercury that existed.

However, within a decade or so, the first decades after Galileo decided to appoint his telescopes up to the heavens, other astronomers had observed both its varying phases and a multitude of transits across the sun. This is a pretty interesting thing. About 100 years later, after all that, 1737, astronomer named John Beavis actually had the extreme, extremely rare opportunity to witness what's called

an occultation, occultation. And this is where, let's see if we can do this. We have mercury. back to this perspective real quick. So we have Mercury. Mercury is closer to the sun, so its orbit, even from Earth, is inside Venus's orbit. So let's see, we have Venus would be like this. It's got a little phase like that.

Here, so an occultation, the orbits of Venus and Mercury from Earth's perspective. actually overlap. So that Venus actually covers up mercury perfectly. And this would be... So Venus right here with its... Back to the Sun now. It's Mercury. And Venus perfectly covers up Mercury.

And this would be a pretty cool thing to witness, I think. But... This guy... John Beavis discovered, he witnessed it, but then realized that it only happens about two or three times a millennia. So it happened in 1737, but it sadly for us, won't take place again for until the year 2133. It'll be cool for some of our great-grandchildren, maybe. So now we you've kind of gone over the ancient history, the etymology of the name, Mercury, the mythology behind it a little bit, and the early smatterings of science that have been useful

in describing some of Mercury's characteristics. Now let's get into the more modern science. We see after science really took off around the year 1500, roughly, especially in Europe, astronomy expanded much more quickly than any time before that, really. And among some of the most tantalizing questions was the length of Mercury's day. Now, because Mars has prominent features, we could witness hundreds of years ago through telescopes. and Venus also was, uh, it was much brighter, so we could at least see the phases of Venus, but it was kind of a haze for a while, so we couldn't see it stay either, but Mercury, it was kind of tantalizing.

We, we had assumptions that because it was so close to the sun, it must have some unique characteristics. that the other planets didn't have, maybe only one side faced the sun at all times. And we were really curious about that. And the question actually remained unanswered for centuries. And this was due mostly to the interference of the atmosphere on Earth. Because, as you know, our Earth has a really thick atmosphere. nowhere near as thick as you know say Venus is but certainly much much thicker than Mercury and Mars and that makes the the seeing as astronomers call it very terrible around the horizon because as you're looking

here in this direction versus more directly up into the sky you have much more atmosphere to actually have the light rays travel through so they get obscured there's a lot more atoms a lot more molecules for the light rays to diffract to bounce off of and disperse and diffuse making the image much less sharp and that was why we couldn't see get a good um visualization visualization of mercury for a while for a while and even in the The 1800s, they had huge, huge telescopes, these ground-based telescopes. Even they, I mean, they were like, you know, 15 feet across, or at least like 10 feet across. These were massive telescopes.

They could see Jupiter's spot and they could see Saturn's rings easily. But they could not make out Mercury for the life of them. It took 20th century technology for astronomers to finally bounce radio waves from the Erescebo telescope. The Erecebo telescope all the way around the other side of the world was able to bounce radio waves off of Mercury in. And they were able to see for the first time some actually geographic features like craters. and valleys on mercury. This was important because it means that they could now

see how long it takes for mercury. Now we can finally draw something here. So if we have a kind of a crater, I guess I'll make it a little more elongated like that. If we have a surface feature of mercury, we know how long it takes to rotate. Timing how long it takes to see that same feature,

rotate once around, and come back in the few in the telescope. So it was cool. Now that we could see what the rotation was, we understood that Mercury actually didn't have a tidally locked orbit around the sun, like the moon does with us, where we only see one side of its face at all. times. By the 1960s, astronomers could see many unique characteristics. There are a lot of things about it that were primarily due to its very close proximity to the sun. They noticed

Mercury's highly eccentric orbit, where it's up to half the distance from the sun. here, let's see, miles at its furthest point from the sun. Whereas its closest point, it's only 29 million miles, which this is a drastic difference. It's the most eccentric orbit out of all the planets. And they also found that Mercury, going into the rotation now, this is probably the one of the most interesting, characteristics of mercury here.

It's rotation. There's two types of things we call days. Mercury rotates for something to rotate once on its axis. So this lettering, for instance, the time it takes for that piece to go all the way on rotation on its axis. And that takes about 59 Earth days. And it's,

entire orbit around the sun all the way around here is about 88 earth days pretty close to exactly one and a half times longer and this means that its orbital rotational resonance is a three to two resonance for every 88 days mercury rotates one and a half times so that means for it to rotate and even a whole number of times, it has to go around the sun exactly twice. So its orbits aren't actually very chaotic. They're actually in a very tightly locked three to two resonance. That means that every three days, two years. So this is...

this is the same as its year versus its sidereal day is what that's called so the interesting part here is that this isn't its day in the sense that we know the day meaning from sunrise to sunrise here we're going to make a distinction between a solar day and a what's called a sidereal day the sidereal day the sidereal day in a in essence is how long it takes for a spot on the planet back up into the heavens. We use the stars as an analogy for a fixed point in the heavens. And let me draw this out for you. It was hard for me to understand. There's a difference between, let's see, if we have, so if we have the sun, the sun obviously, right here,

We have mercury facing the sun. So if we have a spot, mercury, that's a spot on the ground. Let's put that there. For it to rotate once so that this spot turns all the way around. And you know what I have, my little, I used a, I used an old racket ball with a pin and a small screwdriver in it so I can do this. so we have our lighting a little bit different night lit a candle here so we have an idea of what's going on with mercury's day and just right up front it's day there's a distinction between it rotates once that's 59 days but it's solar day what scientists call the sunrise to sunrise is one 176 days or two years on Mercury. And that's due to the fact very simply that Mercury

Rotates so slowly with respect to its orbital velocity that the Sun appears to never really set or at least takes again years to make its way all the way around the planet. The reason I busted out this candle is because the 59-day rotation is called a sidereal day. This is from the Latin word Cetus or Cytis.

I'm not sure how to pronounce that. For star, this is the primary way astronomers to find the rotation of any cosmic object. This is the rotation relative to the stars that are essentially fixed points in the sky. So it's a reliable measurement. So for scales of time on the order of hours, days, or even a few years,

astronomers treat the constellations, whether it's Orion's Bell and the Big Dipper, as though they're permanently fixed on a almost infinitely far-away sphere. So you can imagine we have our sun and our planets going around it and then almost infinitely far off in the distance. It's like a big glass sphere on which the stars are painted. If you're a fly on that sphere up here and you're watching all this action going on,

you don't move relative to the extremely rapid rotations of all the planets and the orbits of the planets and everything going on inside our solar system. So this, from this perspective, if a point on the planet Mercury is out here, let's say this is the sun, so we'll say out here is a constellation, the time it takes for a point

to rotate and point directly back to that constellation is called a sidereal day. Now this is way different than a solar day. Let's see how am I going to see how I wrote this in my little script here. It's representative of a sidereal day. Let's pretend some bright light off in the distance, the stars. This has been 59 days from here to here. Now, if you can imagine, you could see, it's...

undergone its subtended in angle in its orbit. So the Sun is now actually Mercury is now in a different position relative to the Sun from when it first started. By the time 59 days has passed it's undergone about two-thirds of its orbit. So for planets like Earth, there's a small difference but there is still a difference for this rotate all the way around the same star in the sky again

for it to rotate so that the sun is back in the same position in the sky that it's going to have to undergo a slightly longer rotation So the sidereal day, meaning a star or a constellation, returns to its exact point in the night sky from one day to the next,

one rotation to the next rather, is going to be shorter than for that same point to rotate and then rotate a little bit more to make up for the difference of its position relative to the sun. now so that little distinction this being the sidereal day and this accounts for mercury's sidereal day and this being the solar day what accounts for mercury's sidereal day being 59 days and its solar day being 176 days or exactly two of its ears. And if we... Let's bring this camera.

I'll try not to burn it. Maybe we can look at it like this. So Mercury is rotating. It's not exactly like this on Mercury's surface. It doesn't exactly look... It doesn't face the sun all the time, but it's slow. So it takes...

If we start exactly right here, it undergoes a complete rotation to return back to that direction. It takes about two-thirds of its orbit to do that. So as the sun dawns for this guy right here, now we see for him it looks probably like it's kind of morning. and by the time it goes back to its original position, it's maybe mid-afternoon. Slowly the sun's almost setting. It's getting there. And now in another two-thirds of its orbit,

remember, it's going to go three full rotations in two orbits. It's a three-two resonance. So once more, just because I think it's so, so cool, we have the sunrise on Mercury and you can watch it pretend imagine where the sun would be it's like early morning kind of late morning right there

and it's kind of like midday almost and right there we're returned to our original position about two-thirds of its orbit is now complete we need to get back here so the sun is now kind of it's hit its peak

and now it's kind of starting to set and as we continue through another two-thirds of its orbit the sun's just about to set and there we go looks like the sunset and now we're

again we're at nighttime here another two-thirds of an orbit has completed we already hit our year and we're about a third into the second year and then we've completed two rotations already and we need three full rotations

in the same time it takes to complete two orbits around the sun and our last final rotation as we try to have our little tack we see about right here if you can imagine it do that one more time so it's like nighttime rotating around and right about here is dawn, sunrise coming up, but it's moving, it's orbiting so fast

that the day just takes that long to complete. So the reason Earth doesn't have a real big distinction between our sidereal day and our solar day is because that little difference right there is only about, four minutes. So for Earth, for us on Earth over here, our solar pretty much 24 hours, and our sidereal is 23 hours, 56 minutes, and a couple seconds, something like that. So, in 23 hours and 56 minutes, we've returned to looking at the exact same star. And then 24 hours, four minutes later, we've returned to looking at our sun because we've undergone a little bit of our orbit, only about 1,365th of our orbit. whereas Mercury it undergoes

you can imagine two thirds of its orbit by the time it's rotated to face the same star in the sky now let's see what else and we're going to talk about a couple different features about Mercury and the Sun

in fact so the Sun has two characteristics characteristics that make it drastically different than what we experience here on Earth. Because Mercury's orbit is so eccentric, it comes out here and you can imagine it's pretty intuitive when you think about orbits. The speed as it's receding from the sun, so let's make our sun a little bigger. Mercury goes away to its aphelian, its furthest point from the sun, which remembers about double the distance from its closest point you can imagine it's losing a lot of gravitational potential energy the sun is trying to get it back to its closest point

but there's no air molecules in space to slow it down as it moves so the orbit is taking billions of years to slow down slowly but within each orbit Mercury is slowing down here and then gradually speeding up and zipping around speeding up and zipping around like that

that's kind of what it's doing every orbit, every single orbit let's see and the cool part here what I really like is to imagine is the sheer size of the sun in the sky.

So I think, so if we compare the distances of the planets from the sun, again we have, so if we have the sun, we got Mercury, Venus out here to scale, but the sun would, uh, if the planets were pretty much the size of atoms or like little, you know, cells, single cell organisms, maybe that might be to scale.

with the size of the sun right there. But just imagine the size of the sun in the sky. Well, for Mercury, the sun, let's see, the sun for the earth, there's a cool, a really cool diagram. For the earth, if the sun is about this big in the sky, and it is about right. Usually, when you hold your thumb at arm's length, it pretty much covers the sun from obviously Earth

and Venus and Earth are in elliptical orbits as well but to give you a perspective of just how much more eccentric Mercury's orbit is are our perihelian and aphelian sun you can't really notice the difference in our suns and Venus is a little bit closer

so it's I think its sun looks something like that in its sky and then of course it's perihelian perihelian being again the closest

point to the sun in their orbit is really only just a small bit Larger. Now, Mercury is right up next to the sun. So at Aphelian, it's furthest point in the sun, from the sun. It looks something like maybe, oh, I don't know about, a diameter about twice as large as what our sun looks like. So this is Mercury at Aphelian. When Mercury swoops in right here. It gets twice as close to the sun. It gets five times closer to the sun than we are. At our closest point, its sun looks at say, maybe not quite that big. It's sun.

Just imagine looking up in the sky and we have our sun right here. When we look up in the mercury sky and see a sun who in area takes up nine times what we see from here on Earth. So if we're on the mercurion surface, this sun is over here. Dominating, just absolutely dominating the sky. Jesus, that's just, I don't know, it's incredible. It's got to be pretty amazing to really matter. being that close to an object that is just oozing with bursts, continual perennial bursts of nuclear fusion,

matter being fused together and releasing billions of kilotons of energy every single second. Just imagine being that close. So it's huge. The sun looks huge in the sky. And it goes from about four times what we'd see in the sky to about 16 times the area that our perspective of the sun in our sky takes up. So over a period of about eight Earth days, as it speeds up, the sun, of course, is growing from this size to this size.

But what it's also doing, you know, it's taking, if it takes one full year for the sun that traverse half of Mercury's sky, it's going to take 44 days to get from Aphelian to perihelian for the Mercury's position in its orbit. That means from about morning until about noontime, Mercury's sun is going to go from here to here, four to 16 times what we see on earth. And in fact, as it gets to perihelion,

the sun is, or the mercury is speeding up around the sun. And the sun actually begins, it begins to reach a standstill. Because most of the time, its rotation is a little bit faster than its orbital velocity. But because it zooms in so fast, when it reaches perihelian, its rotational velocity is not quite able to keep up with its orbital velocity at that point. And what happens, what ends up happening is really got to be a sight to see.

The sun appears to actually, for over a period of eight days, slow down to a standstill for about a day. We could almost picture it like this. this, the sun goes until it slows down, hits perihelion, pauses, and actually goes backward in its motion, until finally it comes out of its gravitational whip around the perihelium and starts slowing down again, in which case the sun the rotational velocity will again catch up

to its orbital velocity and overtake it allowing the sun to return on its trajectory across the mercurian sky so you can imagine the sun would go and slow down start to go back and then continue on its motion

towards sunset. So to recap a year on mercury is 88 days. A sidereal day is about 59 days, two-thirds of its year. And then because the sun, because it's moving so rapidly around the sun, the sun takes 176 earth days or two years of mercury to go from sunrise to sunrise. In this little thing called the perihelian, it actually underwent a procession, so I'll do a miniature version of it here. It was actually important in proving Einstein's theory of relativity. This is pretty cool.

Despite the sidereal solar day distinction being kind of weird. to grasp at first. It's actually pretty understood, pretty well understood phenomena by astronomers. It's the same reason that our moon is tidily locked to our Earth. It's called gravitationally or tidily locked. It's just where one side faces the, it's gravitational tyrant, if you will, at all times.

and Mercury is approaching that so eventually its rotation will slow down to the point where it will have just one side facing the sun at all times but what's not so nearly as understood

at least it wasn't for hundreds of years after Mercury was first studied by you know Kepler in the in the 1600s was this weird motion let's see

so Mercury has this general shape but what we found out was that because it's so close to the sun its orbit was doing a weird thing

called a procession of the perihelians or a perihelian procession. It was where the point of its perihelian was

dancing around the sun. So every orbit, it got a little bit more offset. For nearly 400 years, astronomers were completely baffled at this

phenomenon. Kepler and Newton's equations all made sense for all the other planets. They predicted their orbits nearly perfectly. Certainly perfectly and accurately enough to where there was really no question of the validity of the equations. But Mercury's orbit was always being a little bit offset and could figure out what it was. This perihelium procession actually even led one famous 19th century astronomer in mathematician to posit a planet called Vulcan. This guy was Urbane la Verrier.

He was actually the discoverer of Neptune. So he had a lot of respect in the community for discovering Neptune. So people listen to him. And he thought, there must be another mass right inside here, ridiculously close to the sun that was pulling, that was pulling on the perturbing its orbit, just a little bit. But for over half a century, he went around and actually gave lectures on it, talking about a new hellish planet.

He won some brief acclaim for it. Ultimately, the existence of old Vulcan was never quite verified. I'm sure that didn't prevent him from living long and prospering, though. It took the application of Einstein's new physics about 100 years after this. This guy was trying to posit a Vulcan, a very volcanic, volcanically active, planet and running with it. It took until about 1915. 10 years after Einstein posited

put forth his special theory of relativity for astronomers to solve this mystery. This was actually before the eclipse of 1990 that I believe the eclipse of the sun, it was eclipsed. The light from around it was able to be detected bending due to the sun's immense gravitational field. So what astronomers came to understand was that Mercury's distance

from the sun meant that it was so close and so enveloped in its gravitational field. The equations of Newton that described all the other planets so perfectly actually breaks down. So, let's see, if we can imagine, just like on all those other TV shows. And so the sun, it's like it's in its gravitational well. Mercury is close enough to be an of true. trapped in it as well. It's almost like on interstellar when they were so close to the black hole

that, of course, that was a gross exaggeration. But the time on the surface of the planet was equivalent to every hour was some crazy, like

seven years or something. But yeah, way out here, you know, for Earth. the gravitational well, it's still trapped in the sun's gravitational well, but it's much experiencing much less of these relativistic effects that Mercury is undergoing. So it's pretty interesting that at distances beyond, you know, the orbit of Venus and Earth and whatnot, you don't, you don't, you don't, you don't, you don't, need Einstein's relativity equations. Einstein's Newton's equations work just as well. But it's when you get a severe warping of space time that Newton's equations just, they break down and they

can't account for the variations in the space time continuum, I guess. And if we wanted to impress someone at a dinner party, what you could say is that all of Newton's laws are accurate, thousands, tens of thousands of years into the future for all the other planets except Mercury. Because, maybe I'll sound like Wesley Crusher here. Because the gravitational perturbations in the space-time field around them they have negligible relativistic effects and so it's only for very strong feelings that

general relativity it has to be used to really understand the uh and predict the motions of the planets i think one one equation i found was it was a partial differential equation relativistic effects cause the actual rotation the orbit itself, sorry, to rotate. So it's, the planet's rotating and it's undergoing an orbit, but the orbit itself

is rotating like that. So it's to think about, I'm just fascinated by how, how we're able to, we have these geniuses like Einstein and Newton and we can predict and accurately predict these fundamental laws of nature.

So it's just amazing. So we've been clearly dancing around the planet itself. We know the history, the early science of it, some cool, some characteristics of its orbit. Now let's go ahead and touch down, rather, on the surface. So after the Earth, Mercury is the second densest planet. denser than either Mars or Venus even. And despite being smaller than the moon's Ganymede or Titan,

it's incredibly, incredibly massive, much more massive than any moon in the solar system. It's huge core, actually. So let's go ahead and draw this. It's 85% of its radius. I'm going to do this. I'm going to draw its thin, thin, Just imagine the core of our planet is something like 15% of our planet.

You wouldn't even see it in this picture here. As far as the radius goes, but Mercury's is 85% of its radius. From here to here, it's 85%. And by volume, it's 40% of its volume. So it's almost half the entire, not even, not the math. It's most of the mass, but it's almost half the entire volume of the sphere-like object. So let's try my best. Let me make it look, because we all know a planet is not perfectly smooth.

And we'll just highlight these lines a little bit. That's pretty good. Because what the star of the show to be noticed and recognizable. So the 85% of its radius, 40% of its volume. So we have the, sorry, kind of messed up on that, but this is the crust. As you can imagine, you know, in the, in any compound, any mixture, heavy objects, heavy materials like metals are always going to sink down to the bottom. and in the solar system in that same way

the bottom is the center of the gravitational well that we in our solar system is the sun in the Milky Way it's the black hole around the Sagittarius A-star and of course

so everything that didn't fall into the sun would have formed densestine and heaviest, closest to the sun. So that's our four terrestrial planets. We call terrestrial, meaning terra firma, meaning earth, and they are rocky, as opposed to the four gas giants,

that we all are pretty familiar with by now. And so the core is made up of mostly iron and all these heavy metals because of that natural tendency for heavier objects to settle in closer to the bottom of any gravitational field. That huge core means that a lot of the magma is flowing relatively just beneath the surface as well. And I don't think it's very active volcanically, if at all. all, it might not be very much. Or that magma as a slip definitely affects different things like the magnetic field, the heat,

even the size of the whole planet. In fact, astronomers have concluded that over a billion years the making such a significant part of the planet as some of the magma might have escaped somewhat a little bit, just generally being so close to the surface, being so absolutely ridiculously freezing temperatures of space, it generally cooled the planet. And when you have cooling, things, everything except ice, it contracts when it cools. It gets smaller. So what that means is that the planet actually has shrunk by up to about 4,000 miles.

in its diameter as the heat is lost to space which is pretty amazing as for its atmosphere it has a lot of mass because it's so dense but it's still you know it's still a little guy

has just 38% of Earth's gravity and because of this you know what might bounce like this you're bouncing probably three times as high. Mercury has roughly the same gravitational field as Mars, actually,

which is way bigger than Mercury. So that's pretty crazy to think how much a dense planet, a densely heavy metal planetary core can act as a gravitational source. It's pretty cool. This doesn't be Earth. And this is Mercury's gravity right there. And because of this light gravitational field,

even though it's, you know, relatively for its size pretty strong, it hasn't been able to substantially attract, of course, any moons or rings, but also any atmosphere, any significant atmosphere. The mercurial atmosphere is actually so thin, that it's closer to a true vacuum than anything we've been able to artificially create here on Earth. Now, there's still a measurable atmosphere,

but the density of air molecules is so thin, that it's actually a pretty cool statistic to realize that our space station is about, I guess, 250 miles, I think, miles in altitude. Mercury's atmosphere is as thin as not what's up in the space station, but double that, almost triple that, over 600 miles out of the Earth's atmosphere, or rather in altitude away from the surface of the Earth, 600 miles, is a good. 600 miles is equivalent to the surface of Mercury. So the space station is traveling at something like 17,000 miles per hour. There is pretty much non-existent atmosphere. And so you can imagine how unimaginably thin, I guess.

So maybe you can't imagine it. It's ridiculously thin. It's insignificant and certainly not enough to retain any substantial heat. You rode any creators or any geological features like the very dense atmosphere on Earth. Here it does. You know, just like Vulcan was supposed to be just this searing hot planet being that close to the sun. Well, Mercury is not much further away than they thought Vulcan was supposed to be. actually. So you would think it's definitely by far the hottest planet in the solar system, right?

It is pretty dang hot the side, especially that's being melted by the sun, going up to something like 800 degrees Fahrenheit during the day. So this is the side that's being blasted by the sun. is 800 degrees Fahrenheit. But that actually is cooler than the surface of Venus, which is actually the winner of the hottest planet award. And I guess that's pretty appropriate, given the fact that Venus is the goddess of love. And that's due to her special features,

being her thick, voluminous atmosphere. acts like a super efficient insulator, keeping most of her heat in. So that explains why Venus out-competes Mercury for the hottest planet award. In Mercury's lack of atmosphere also exposes it to extreme temperature changes. So during the day, as it's being bombarded by the sun, it's up there. 800 Fahrenheit, but during the night, you know, after a mere 44 days, once it does eventually set, its temperature on the other side, the dark side goes all the way down and all the way around the other side of the planet. At night, it has no atmosphere remember. So immediately all that heat,

even the insulated heat in the crust that's that the crust has absorbed in the molten rocks, you know, they're sitting there at 800 degrees. After a couple weeks go by, exposed to the dark, cold, still recesses of space. It drops it all the way down to something close to negative. 280 degrees Fahrenheit And so we have something like a couple miles of Thick atmosphere here on Earth

That prevents all our radiation from Leaving Whereas they On Mercury They have no atmosphere to really insulate them at all So all that heat is lost immediately There's nothing preventing it from scattering off the planet

and receding into space so though Mercury's magnetic field at the surface has really only about 1% of what Earth is it greatly still interacts with the magnetic field of the solar winds you know being so close to the sun

being five times closer to the sun than we are at its perihelian, Mercury is undoubtedly bearing the full brunt of the force of these solar winds. Mercury is pretty small, but it packs a punch with its heavy iron core. It has about a magnetic field 1% of what Earth's is that still greatly interacts with all the, solar winds that are always barraging it. And this sometimes, interestingly, creates a... Creates funnels.

Creates these magnetic field funnels. So it's pretty wild. It's magnetic field is actually offset from its core. I'm not really sure where I wrote that down, but... It's magnetic field. It's kind of doing something like, when you get this, being hitting the field and then being funneled down to its surface, where it actually strikes the actual surface knocking off neutrally charged atoms

and sending them on a loop high into orbit. What happens here is that any little atmosphere that Mercury might have had is kind of knocked away as it's washed over by the solar winds, the very charged, highly charged particles being emitted from the sun at all times. These are the things that interact with the oxygen, nitrogen, and other chemicals in our atmosphere to create auroras at our poles. And so it's constantly having its atmosphere replenished, if you will. So as it washes some away,

It knocks off other negatively charged particles or neutrally charged, charging them negatively and sending them over up and away, spiraling into the altitudes of mercury, and to create a very flimsy atmosphere. Now, the surface already kind of made a little crater right there because mercury is distinctly very visibly covered in craters like we said we're as no real volcanic activity to smother and smooth over any of these rigid rocky surfaces and it has no real atmosphere to erode away even over millions of years even billions of years even no real atmosphere no wind no rains no rains to slowly wear down and smooth out these craters. So they're just basically as sharp and vivid as they once were,

or as they were from the get-go. The surface is similar to the moons, so much of its scarring is actually due to ejecting chunks of bedrock. So while we have many of its craters, obviously made from meteorites in comets, smacking into the surface. What happens as well is that when this gets hit, maybe it gets hit. Craters being formed also happen.

Pieces, huge chunks of the crust itself is ejected into orbit. not quite orbit but high up into the atmosphere where it falls down crashing in ejecting chunks of bedrock and they fly silently

into the highest altitudes silent because there is no atmosphere through which the sound can travel and then they're splashing down all around forming new craters new secondary craters

Sometimes even finer, more reflective particles from either the crust or the impact object are flayed out, and they create these streaks, these bright, bright streaks. We call crater rays, almost looking like a bag of flowers smashing into the surface. Visibly see these in a lot of the pictures of mercury. one of the brightest spots is actually from a crater left around a 40 mile wide crater, the crater rays rather, called quite Kuiper from the astrophysicist, whom the Kuiper belt is named after, the series of rocks that Pluto is the innermost, one of the innermost of and most significant of. And here, it's very important to take a, um, to,

Consider the rapid speed around the sun that Mercury is orbiting at and how this might affect the violence of a collision with another object. If you have a comet traveling into the solar system and we have Earth over here, when it hits Earth, that's a violent impact. When it hits Mercury, that's a whole other story. because Earth is over here doing a nice graceful orbit. Mercury is over here running like a dog chasing its tail. Its orbital velocity is so fast, especially when it's going under undergoing perihelium, that a comet smacking into it,

almost equivalent to something being hit by a car going 10 miles an hour versus maybe 80 miles an hour the impacts are so much more violent and astronomers actually I read that astronomers actually think possibly the most violent impact in the entire solar system at least the terrestrial planets

because we can't really see what happens in the gas giants once something falls into them is possibly the coloris basin on Mercury. To give you an idea of the speeds, let's see, international space station is traveling at about 17,000 miles an hour. The planet Mercury is traveling roughly about 100,000 miles per hour. this is incredibly fast

and comets actually once they get that close into the sun and they're reaching their perihelian they're going to be reaching that same speed and so to watch two objects colliding in a 200,000 mile in impact and our impact it's got to be a sight to see back in 1970

I think it was. The first spacecraft to visit Mercury was called Mariner. Mariner 10. And this discovered a huge, what's called a basin on Mercury. Now, these are craters that are 150 miles wide or more. So you have small things, maybe a grain of sand, a rice, maybe a bus, maybe even the size of a stadium. But when you have things that are miles wide, you get planetary levels of geological impacts.

And the coolest part about this is that this calores basin, coloris basin will say, that's this bad boy right here. And they think that it smacked mercury so hard, it reverberated. incent compression waves running through its core and the surface. So it's got these, so if this is it, it's got these waves, compression waves have rippled through the core. And then also through the crust as well. They actually are going to, with enough impact, it's going to lift up the rock. It's going to shake the other side of the planet. And that's actually what happened on Mercury. And this is probably, probably the most astounding thing about Mercury that I found

was that there's a place they call the peculiar terrain. It's made up of jumbled chaotic hills ranging from 200 on the way to 2,000 meters, 2 kilometers high. And geologists believe that that's exactly what happened. It was compression waves, rippling around the crust and through the core and meeting and converging and heaving up the bedrock in the crust into piles. And that kind of energy is very peculiar. Finally, I want to just discuss the most recent probe that we've sent to investigate Mercury's environment, and this was named Messenger, happily enough, as Mercury is, of course, the messenger of the gods.

It was launched in 2004 in stands for Mercury, Surface, Space Environment, and for Environment, and for Environment, GE, Geochemistry, and the last R for ranging. So it was the Mercury Surface Space Environment, Geochemistry, and Ranging Probe. This was launched on board a Delta 2 rocket to study Mercury's chemical makeup, geology, and magnetic field. While in orbit, Messenger actually concluded the presence of high concentrations of magnesium and calcium found on the surface. So I believe it's magnesium and calcium is CA. I might be wrong though.

It also detected another peculiarity about it. It was in Mercury's magnetic field. And that was where I talked about earlier. It appears to be offset to the north of the physical center of the planet by a significant amount. know what this means but apparently neither do they from what i could find at the moment they just know it's a peculiarity of kinetic field probe met its fate in 2015 once it ran out of energy yeah the mariner they think is still in orbit the sun in the same at the same radius from the sun as mercury is but the messenger probe, they specifically crashed it out of orbit.

After 10 successful years of observing the planet, when it used the last of its fuel and subsequently fell out of orbit, crashing into the planet, getting a couple interesting pictures along the way. Now, before it crashed, it confirmed the existence of both carbon-rich, organic, compounds at its north pole so we're gonna pretend that this is its north pole right here because you have craters when the sun's hitting here at the north pole just like you're on earth that the sun will never hit just due to this the sheer angle at which the rays are

hitting the planet so you have some craters most of which they're never heating up there's no atmosphere to trap heat on the equator and send it north so these things are always exposed to temperatures of space and what they found and this is really amazing it's really something that that happened so that tells us that even on the most extreme planet pretty much other than maybe venus we have or organic compounds in water ice, the stuff of life. This is fascinating because what it means is that the stuff of life certainly exists outside Earth now. We know that.

And therefore very probably exists on many other worlds yet to be even discovered and certainly explored both in, and out of our solar system. So we don't know is yet to be discovered. That my friends is why Mercury is so interesting. We'll be enjoyed it. Guess this one ran a little bit long. But I had fun.

It was a lot of new, interesting things about it. Gave us some more insight into our home neighborhood, the solar system. and intrigued and sparked my curiosity about just what else is out there. And certainly fuels our imagination for just how probable it is that life exists somewhere outside of Earth. Sleep well, guys, and we'll see you next time.