Hey, it’s you! I’m so glad you could make it! This is the third chapter of our little tour of the Solar System and I was beginning to think you weren’t going to make it. For the obligatory recap of the tour, the first chapter was the introduction, while the second was all about the Sun.

Since the last stop was the Sun, we should be moving onto the next celestial object, which is Mercury; the first planet from the Sun. The problem is, I feel it could be important to discuss just what a planet is, and how they are different from a dwarf planet.

I briefly mentioned dwarf planets in the introduction, because let’s face it, they sound made up. It’s ok to admit it, you’re among friends. Dwarf planets are real, but they’re not as famous as their larger siblings; however they are no less important. Seriously.

Ok Scott, stop talking and actually say something! What is a dwarf planet? That is an insightful question, so here is a ridiculous answer. Let’s hop in our DeLorean time machine of the mind and travel back in time to visit three important dates: 1930, 2005 and 2006.

In 1930, a planet was discovered by Clyde Tombaugh, which was later named as Pluto.¹ Pluto become known as the ninth planet of the Solar System, and history and science textbooks would never be the same. Um….that’s not truly accurate is it? I remember learning about Pluto at primary school: we had nine planets in the Solar System and even though Pluto was the smallest, it was still identified as a planet.

For over 60 years, Pluto got to hang out with its older siblings, because it was still identified as a planet. Well, until 2005 it was. Over the years, technology has advanced with new developments, that has allowed humanity to view the universe in amazing new ways. Because of this, new objects were being discovered in our Solar System and beyond; but especially in and around the Kuiper belt, which is a disc like region of space, beyond Neptune.

And just so we are on the same page, Pluto resides in the Kuiper belt.

So back to 2005. Among the media released discoveries of Makemake and Haumea, another object was discovered: Eris. When the first measurements of Eris were released, it appears that it was actually larger than Pluto, even though it was further away. This development led a lot of scientists to call for the reclassification of Pluto. They also thought another object named Ceres, which was discovered in 1801, finally needed a permanent classification as well.

We can now move to 2006, which was Pluto’s least favourite year ever. Enter the International Astronomical Union (IAU). The IAU has been described as:

…a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and development through global co-operation.

Basically the IAU get to decide things about astronomy.

In 2006, the IAU held a general assembly, with one of the issues concerning Pluto and what to do about it; along with some other objects. This led to the definition of a planet, which consists of three criteria.

1.) Is in orbit around the Sun.

2.) Has sufficient mass to assume hydrostatic equilibrium.

3.) Has “cleared the neighbourhood” around its orbit.

The first criteria is obvious, the planet must orbit around the Sun.

The second criteria talks about the planet achieving hydrostatic equilibrium, which is just a shape that is nearly round.

The third criteria is about when a planet orbits the Sun, it must be the most dominant gravitational object, in that orbit. It means the planet needs to be able to sling or clear the neighbourhood of any other smaller objects in its path.

When Pluto was measured against these three criteria, it passed the first and second, but failed the third. And a long story short, Pluto was declassified as a planet and reclassified as a dwarf planet, along with others.

Textbooks were rewritten and suddenly Pluto no longer could sit with the cool kids, but needed to sit at a different table.

This being the case, a definition for a dwarf planet was established.

1.) It must orbit the Sun, and not be a moon.

2.) Has enough mass to be round.

3.) Has not cleared its orbit of debris.

To date, our Solar System has eight planets that meet all three planetary criteria. Starting with the closest to the Sun, we have Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

As for dwarf planets, they are planetoids that fail on one, two or even all three of the IAU planetary criteria; but pass all of the IAU dwarf planetary criteria. To the best of my understanding², there are five official dwarf planets in our Solar System. Starting with the closest to the Sun, we have some amazing names like Ceres, Pluto, Makemake, Haumea and Eris.

There are five other dwarf planets in the Solar System, which are known as Trans-Neptunian objects or TNOs, that are waiting to be officially recognised as dwarf planets.³ In order from the Sun, they are Orcus, Salacia, Quaoar, Gonggong and Sedna.

Basically that’s it. A planet is identified as a planet, because it passes all three IAU planetary criteria, whereas the dwarf planets, fail at least with one of the planetary criteria. Whether this is fair, is another story for another day. Clear as mud?

That’s it for another week, I’m sorry. I’ve got to go and bore my wife with rugby and football scores now. Thanks once again for reading, following and subscribing to Some Geek Told Me; it means a lot. Remember to walk your dog; watch a banned movie; stay away from Sour Cream and Chives; and I’ll see you next week.

¹ The story behind Pluto’s name, deserves its own tv movie.

² Let’s face it, that isn’t very much.

³ Again, to the best of my understanding.

Hi, welcome to my tour of the Solar System. The first chapter of the tour was last month, which woefully described why the tour is taking place and where we would go. But hey, the tickets are free, even though the tour guide is not officially affiliated with any tour group.

For our first expanded stop on the tour, we’re starting with the main attraction: The Sun. It’s always there, very dependable, just like an ideal boyfriend/girlfriend; but what do we really know? Short of Facebook stalking, we actually know quite a bit about the Sun. Let’s start with covering some information about everybody’s favourite natural fusion reactor.

The Sun is crucial to developing and maintaining life on our little ball of happiness. The Earth receives light and heat from the Sun; but it also powers photosynthesis in plants, the climate, weather, and ocean currents. Without the Sun, life on Earth would be like Frankenstein’s monster, without Frankenstein; because Frankenstein and the Sun both bring life. Except I don’t think the Sun has ever had one of its creations, sneak into a bedroom and strangle a bride on her wedding night. Yet.

I’ve said this before, but the Sun is actually a star. It’s like the trick question you get asked, “What’s the closest star to Earth?” So your answer could be, “Proxima Centauri.” If it was, you would be wrong…because, say it with me, the Sun is a star!

If you’re on a first or second date, you might suggest a walk together in starlight. Your date will probably correct you, by replying it’s daylight outside and the stars are not visible. You can then calmly mention that the sunlight that we are experiencing is produced by the Sun; the Sun is a star; stars produce starlight; so therefore, we are walking in starlight. Your coolness and hotness factors will increase exponentially; like a geek.

The Sun is known as a yellow dwarf G-type main sequence star. Scientists are extremely clever and innovative people, but sometimes they can come up with some pretty bizarre names for things. If you saw that name on a Tinder profile, I’m sure you would be swiping left, but let’s look at the name and what it means.

Spoiler alert, but names tell you exactly what things actually are and what they do. Just like a green toaster, is a machine that’s green and toasts bread, or a book called, Pride and Prejudice, features two main characters that experience both pride and prejudice, or a man that dresses like a bat is called Batman, or a Horseshoe crab that…wait a minute.

There are many ways to describe main sequence stars in far better scientific terminology, than from a man that describes Azure, Royal Blue and Navy Blue, as Light Blue, Blue and Dark Blue, respectably.

A main sequence star is a star that crushes hydrogen atoms together, to form helium atoms in the star’s core. This is known as nuclear fusion, because it involves the fusion of atoms. It’s this process that releases the energy to make the star stable. This energy is pushing outwards, and it counteracts the force of gravity, which is trying to collapse the star. The Sun finds equilibrium through this, allowing it to continue to fuse atoms and release energy.

Let’s look at the G-type part now. Stars can be graded based on various factors using Stellar classification. These factors can include spectral characteristics, temperature, mass, luminosity and absolute magnitude. This puts our burning ball of hydrogen near the centre of the classification system; which is a G-type star. Not too hot, not too cool, it’s just right.

As for the another part of the name, yellow dwarf, the Sun is neither. It’s not a dwarf, because the Sun is about 1,392,700 km (865,000 miles) in diameter; which is 109 times the size of the Earth. That also means about 1 million Earths would fit inside the Sun. As for the mass, the Sun is estimated to be 1.989 x 10³⁰ kilograms. That’s a strange looking number, but what it means is that the Sun’s mass is 300,000 times that of Earth. There are other stars in the universe much larger than the Sun, but that is another story for another day.

Continuing with breaking your perception of our local star, the Sun is not yellow or orange. Yes, yes, I know yellow is in the name; but that doesn’t mean it’s accurate. Hey, Science, is a Horseshoe crab actually a crab? Hollywood and nearly every picture book have been lying to you, for your entire life. I’m very sorry, but the colour of the Sun is actually white.

So how do we know that the Sun is white? The Sun produces a lot of different light, which is a type of radiation; which in turn, is part of the electromagnetic spectrum. The Suns emits radio waves at different frequencies, as well as microwaves, infrared waves, visible light, ultraviolet waves, and X-rays; but not gamma rays. Gamma radiation is very different, just ask Bruce Banner.

One way to explain this, is that if you have ever played with a prism, witnessed a rainbow in the sky or seen The Dark Side of the Moon album cover by Pink Floyd, you’ll understand that visible light can be broken up into separate colours; violet, indigo, blue, green, yellow, orange and red. All of these colours have different wavelengths.

When visible light passes through a medium and changes direction, this is called refraction. When visible light is split into the colour spectrum, this is called dispersion. In nature, visible light is being emitted from the Sun; so visible light contains all of the colours of the rainbow. And this works in reverse, because just like Captain Planet, when you combine all of the colours of the rainbow, you make white light. And this is a key point: visible light is white light. Visible light is sunlight, which is created by the Sun. So if visible light is white light, and white light is created by the Sun…the colour of the Sun is white.

I’m sure someone a lot smarter than me could do a better job at explaining this concept, but I don’t get paid for this, so I can’t hire any scientists to write this for me. Are you impressed with the Sun yet? No? Alright, let’s do some more!

The Sun is about 150 million km (93 million miles) from the spinning sphere of delight known as Earth. This distance is actually known as an astronomical unit (AU), which is the mean distance between the centre of the Sun and the centre of the Earth. This doesn’t mean that it’s always that distance, because both the star and the planet are moving through spacetime.

The Sun is pretty jacked too. It makes up 99.8% of all the mass in the solar system! Because of this, it never misses leg day. It’s also made of gas and plasma; which is the fourth state of matter, after gas, liquid and solid.

You may have heard that the Sun is old. Not as old as Mr. Burns from The Simpsons, but still pretty old. The Sun is about 4.6 billion years old. Let that sit with you for a moment. 4.6 billion years old. That is mind crushing; but just to dial it up to 11, the Sun is only half way through its life span.

For the interior of the Sun, a visit there would be…unpleasant, if you could stay there for any length of time. The Sun’s mass is made up of 70.6% hydrogen, 27.4% helium and 2% heavy elements like oxygen, nitrogen, carbon, neon, iron and others.

The Sun also has six different layers, which include the corona, which stretches 8 million km (5 million miles) above the Sun’s surface; the chromosphere, which is 400 km (250 miles) and 2100 km (1300 miles) above the solar surface; the photosphere, which is from the surface to about 400 km (250 miles) above that; the convective zone, this zone extends from a depth of about 200,000 km right up to the visible surface; the radiative zone, which has a depth of 515,000 km to 200,000 km; and the core, which is 170,000–140,000 km in depth (106,000-87,000 miles).

As you would expect the temperatures; just like the prices at the corner shop for ice cream, vary a lot. The temperatures are between 6,000 °C (11,000 °F) to 4,000 °C (7,200 °F) in the chromosphere; about 5,500 °C (10,000 °F) in the photosphere; about 2 million °C (4 million degrees °F) in the convective zone; between 7 million °C (12 million degrees °F) to around 2 million °C (4 million degrees °F) in the radiative zone; with 15 million degrees °C (27 million degrees °F) in the core.

With the corona, the temperatures range from 1 to 2 million °C (1.8 million to 3.6 million °F). This is interesting, because it means the upper atmosphere of the Sun, is actually 500 times hotter than the surface. Scientists are still trying to figure this out, along with why a Saiyan’s hair is always so perfect.

On a more serious note, I want to talk about the sheer power of the Sun and what it can actually do. We know that in the Sun’s core, the pressure and temperature is so high, it can fuse atoms together. When this happens, it releases a huge amount of energy.

To understand this, every second, of every single day, the Sun’s core fuses about 600 million tons of hydrogen into helium, which converts 4 million tons of matter into energy. This nuclear reaction is the energy equivalent of about 10 billion hydrogen bombs each second. Every second of every day.

That is 2 billion times more powerful, than the Tsar Bomba, the world’s largest nuclear bomb. Every second of every day.

The Sun produces enough energy every second, for almost 500,000 years of the world’s current energy needs. Every second of every day.

The energy that is released in the core, takes the form of a photon; and this is the source of the Sun’s light and heat. Photons are trapped in the core anywhere between 10,000 and 170,000 years, before they can escape. Once a photon makes to the surface of the Sun, it will only take eight minutes to travel from the Sun to reach Earth and you. Science is so cool.

And would you like to know what’s crazier? I haven’t even discussed the other things the Sun creates like sunspots, solar flares, the solar winds, coronal mass ejections, magnetic fields and neutrinos, or the gravitational influence it has on the rest of the Solar System, to name a few.

The Sun is glorious, beautiful, powerful, and yet it’s still terrifying. We have learnt so much already about our stellar neighbour, but with many new discoveries to come.

I hope the first stop on our tour has made sense. Please let me know if it does. And with that, I’m done. There are so many bags under my eyes, I could use them for shopping; so I need to go to bed. Thanks for reading, following and subscribing to Some Geek Told Me. This project keeps me off the streets, and prevents me from dealing comic books in dark alleys at midnight. I’ll see you next week.