Blog 4: Systema Cosmicum

History Channel Portrait of Galileo

Galileo was one of, if not the most revolutionary astronomer of all time. He lived at a point where the Catholic Church controlled a large section of public and private life, but they were also seeing their power wane through the Protestant Reformation, championed by Martin Luther (among others). The Catholic clergymen were worried, and Galileo did nothing to squash that fear. His book Systema Cosmicum posited that the Copernican theory of heliocentrism was in fact preferable over any geocentric model, and he gave ample (though sometimes erroneous) proof of this.

In most previous astronomical work, it had been assumed that the Solar System was a perfect system because it was in the heavens, and biases surrounding the nature of such perfection naturally snuck their way into Science. For example, it was believed that planets were all perfectly spherical with no deformities, and that they all orbited around the Earth in perfect circles rather than ellipses. The Earth, which was seen to be the center of God’s creation, was naturally put in the center of the Solar System models, creating unreasonably complicated mathematics around explaining the motion of other planets.

Systema Cosmicum was put on the Index of Forbidden Books by the Catholic Church because of how it depicted the Pope (who’s ideas are represented by the character Simplicio in the book) and because it championed the idea that astronomers and philosophers (chiefly Aristotle, who the Catholic Church was based upon) had been wrong about both geocentrism and the idea of perfection in the celestial bodies. Through pointing out the existence of sunspots and mountains on the Moon, Galileo was able to show that there was nothing perfect about the Solar System, or at least not perfect in the way that the Catholic Church and leading astronomers had posited for hundreds of years. Galileo was called a heretic for his beliefs, and would be sentenced to house arrest for the remainder of his life.

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Blog #4

Composition

-The solar system is primarily composed of the Sun, which makes up about 99.8% of its total mass. The Sun is primarily composed of 74% hydrogen and about 24% helium with some amounts of heavier elements. Planets in our solar system are divided into two main groups based on their composition: the terrestrial planets (Mercury, Venus, Earth, and Mars) which are mostly composed of rocky materials, and metals, and the Jovian planets, (Jupiter, Saturn, Uranus, and Neptune) which are primarily composed of hydrogen, helium, with relatively low densities compared to terrestrial planets. Dwarf planets like Pluto, as well as small bodies like asteroids and comets, are composed of rock, metal, and ice, with some containing organic compounds. Moons can have diverse compositions that can be ranging from rocky bodies similar to asteroids to even icy bodies. The asteroid belt, located between Mars and Jupiter, contains rocky and metallic objects that are remnants from the early solar system, while the Kuiper Belt, beyond Neptune, contains icy bodies and dwarf planets.

Image

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Blog 4

Dr. Suess’ genius

In first grade, I was really mad. Honestly, I was INFURIATED. I had just heard that they had officially reclassified Pluto as a dwarf planet. For me, that meant that the pneumonic device I learned from my Dr. Suess’ book was a complete lie. In reality, the reclassification of Pluto was much more informative and logical than first grade me realized. 

Before the reclassification, we saw Pluto as a round object and thus classified it as a planet. But after discovering the surface of the planet as extremely icy (like asteroids) and that it has an extremely small mass, the only real difference was that the object was slightly larger than its Kuiper Belt counterparts. The new classification allows astronomers to group objects that have a large enough mass to be round, but do not possess any of the other characteristics of a planet within our solar system. The reclassification honestly gave me more questions about our solar system and the universe, leaving me eager to learn more about it all. Maybe making me a little angry helped me learn more afterall.

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Kepler-452b

Kepler-452b is an exoplanet about 15 light-years away from us.  It is notable because it is the most Earth-like planet that has been discovered so far.  It is 60% larger than Earth, which is certainly significant, but it has an orbit that lasts 385 Earth-days, and it orbits only 5% further from its star than Earth.  For the Kepler mission, this represents a tremendous amount of success in its effort to find Earth-like planets, but it is far from the only one.  Just in the Kepler-452 system, there are other planets that attracted some attention, like Kepler-452h.  No matter the ultimate result of any of these individual planets, the fact that multiple planets can be found in individual systems near ours alludes to a universe rich in the kinds of habitats and materials life is made of.

(https://www.nasa.gov/news-release/nasas-kepler-mission-discovers-bigger-older-cousin-to-earth/)

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Sideways Wonder, Uranus

Aside from being named after Jupiter’s progenitors rather than his offspring or contemporaries, Uranus has the obvious distinction from having its axis be almost horizontal, meaning it rotates on its side like a wheel rather than like a top, possibly due to a drastic collision it suffered while forming that it never bothered to correct.

This unique movement pattern comes with some interesting climate patterns. The poles only experience one day per Uranian year, meaning there’s 42 Earth years of consecutive light followed by 42 years of darkness. Seasons on Uranus essentially mean whether or not you get sunlight at all.

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Combining Forces: Nuclear Fusion in the Solar System

Business Insider Ignition Image

Shown above is from the National Ignition Facility, where scientists successfully produced (and reproduced) a nuclear fusion reaction that had more energy output than input. The underlying math behind this lies in E=mc2, which shows that Mass (m) can be converted into a large amount of energy at the sacrifice of just a small amount of matter, as the multiplier of the speed of light squared takes the small amount of matter and creates a large amount of energy produced.

Nuclear fusion usually takes place in the Sun, where incredible pressure and temperature battle the repulsive forces between the nuclei of atoms, eventually winning and combining the two. Often in nuclear fusion reactions, two Hydrogen atoms (who’s nuclei have just 1 proton) combine, creating a deuterium and releasing a positron and neutrino, then a Hydrogen ion (a proton) fuses with that deuterium to create Helium-3 and releasing a photon. After that Helium-4 is created by the fusing of two Helium-3 nuclei, necessarily releasing two protons.

Gamma ray photons eventually make their way from the inside the Sun to its surface and are emitted from the celestial object as sunlight.

Gravitational forces are the standard for nuclear fusion reactions, as it is by far the most common natural occurrence of conditions needed (high temperature and pressure). Because the Sun is so massive, the gravitational pull towards its center is also much stronger than any other celestial object in our Solar System, meaning that it is able to create the conditions necessary for nuclear fusion to take place.

In the case of ignition on Earth as performed by the NIF, gravitational pressure was substituted for powerful lasers that create a similar environment (in terms of pressure and temperature) for frozen hydrogen isotopes. Ultimately, they were able to create such great pressure and temperature that fusion took place, and more energy was produced than was put into the system, a historic achievement.

NIF Ignition Article

Business Insider Article

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Crazy Stars

Stars like our Sun are considered “ordinary” and quite common. They produce energy through hydrogen fusion. A weirder type of star is a white dwarf. These are stars that at one point produced energy through hydrogen fusion, but have run out of hydrogen, and do not have the mass to carry out fusion energy reactions with heavier elements. Instead, these white stars sit idle, cooling down for billions of years. A white dwarf star has about the mass of our sun, with about the diameter of earth. The atoms within a white star are packed so tightly together that they exert an outward degeneracy pressure, as the particles are packed as tightly together as the laws of quantum mechanics allow. 

Another type of weird star is the neutron star. Created by the collapse of a star’s core during a supernova, these stars are only 10 km across, but with a mass greater than the sun. They are made almost entirely of neutrons, as protons and electrons within it are so closely packed that they combine into neutrally charged neutrons. In fact, if a 10km wide neutron star appeared in Nashville, it would condense the entire earth into a size no thicker than your thumb. Really crazy!

White Dwarf Illustration – Courtesy of NASA
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Crazy Stars

Stars like our Sun are considered “ordinary” and quite common. They produce energy through hydrogen fusion. A weirder type of star is a white dwarf. These are stars that at one point produced energy through hydrogen fusion, but have run out of hydrogen, and do not have the mass to carry out fusion energy reactions with heavier elements. Instead, these white stars sit idle, cooling down for billions of years. A white dwarf star has about the mass of our sun, with about the diameter of earth. The atoms within a white star are packed so tightly together that they exert an outward degeneracy pressure, as the particles are packed as tightly together as the laws of quantum mechanics allow. 

Another type of weird star is the neutron star. Created by the collapse of a star’s core during a supernova, these stars are only 10 km across, but with a mass greater than the sun. They are made almost entirely of neutrons, as protons and electrons within it are so closely packed that they combine into neutrally charged neutrons. In fact, if a 10km wide neutron star appeared in Nashville, it would condense the entire earth into a size no thicker than your thumb. Really crazy!

White Dwarf Illustration – Courtesy of NASA
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So what is a Black Hole?

by me

A black hole is an astronomical object in space where the gravitational pull is so strong that nothing can escape from it, including light. The “surface” of a black hole is known as the event horizon.

Black holes are undetectable by telescopes because no light can escape from them; However, they can be detected through their interactions with nearby matter. For example, when a star gets too close to a black hole it can be broken apart, and as the gas from the star falls into the black hole, it heats up and emits X-rays and radio waves that can be detected by astronomers. Here’s a visual of how that may look like:

by NASA, ESA, Leah Hustak of STScI

Additionally, the gravitational influence of black holes can affect the orbits of objects around them, which provides further evidence for their presence.

Black holes vary in size, from small (just a few times the mass of the Sun) to supermassive (millions or even billions of times the mass of the Sun). Some of these massive black holes can reside at the centers of galaxies, like our Milky Way.

More on black holes can be read by clicking here.

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Far Out, Man

Telescopes laid the foundation for everything we know about space, but they can only get you so far. If you don’t particularly feel like removing the planet’s entire atmosphere to get a better view, spacecrafts do a pretty good job of getting a closer look.

Flyby spacecraft are the simplest and least expensive; they can be light as long as they can withstand the trip to space. The lack of air friction up there also saves on fuel. Flybies, as the name implies, move past planets and transmit images of them back to Earth, essentially serving as a long range cameras and spectrographs. Orbiters are more specialized, being built to stay in a celestial body’s orbit, in turn allowing a more sustained stream of data. Landers and probes go the extra mile and land on the celestial bodies, allowing for an even closer look. Probably the most elaborate type of data retrieval spacecraft is the type that literally retrieves data and bring it back to Earth: sample return crafts, which have already been used to collect comet dust and are aiming for Mars next.

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