When I learned the order of the planets in elementary school, Pluto was still considered a planet. About 14 years ago, it was demoted to a dwarf planet. The International Astronomical Union has three criteria in determining planetary status. It is in an orbit around the sun, it has sufficient mass to assume hydrostatic equilibrium, and it has cleared the neighborhood around its orbit. To be a planet, you must have all three. Pluto actually orbits with other surrounding stuff in its “neighborhood”, meaning it can not count as a planet, and this, was given dwarf planet status. Jim Bridenstine from NASA argues that the IAU’s decision was unscientific, and was used as a means to keep the number of planet’s down to a manageable number instead of being forced to reevaluate the entire solar system. For now, Pluto remains a dwarf planet, but here is to Pluto lovers like myself: there is hope Pluto could once again be a planet.
Cosmology is the study of the origins and evolution of the Universe. Cosmos is actually just another word for universe. My favorite theory is the theory of the Multiverse (thank you Spiderman!) This theory states that we are just one bubble in an infinite series of bubbles, and that the differences between the Universes are called “parallel universes”. Together, the universes comprise of everything that exists, and that is infinite as we grow, change and evolve. It is hard to wrap my head around sometimes, but I really became interested in it thanks to the Spiderman movie!
Nuclear Fission is a reaction (or radio decay process) in which the nuclear of an atom splits into two, smaller and lighter nuclei. This process produces gamma photons, and releases extremely large amounts of energy, which we then use to make our own usable energy. The release of the heat energy can be used to spin turbines and produce electricity. Uranium is the most common “fuel” for nuclear fission. Uranium is not a renewable energy source, but is found commonly worldwide. There are two types of reactors: Thermal-Neutron and Fast-Neutron Reactors. Thermal-Neutron Reactors are the most commonly used types today, while Fast-Neutron Reactors are currently seen as the next step in progression for Nuclear Energy.
Throughout this unit, we learned about tides, their causes and what influences them. In preparing for this blogpost, I came across two different kinds of tides (besides high and low tide) called “spring” and “neap” tides. These tides correlate with the moon phases, in that spring tides occur during the new or full moon, and the neap tides 7 days after the spring tides.
Spring tides are more extreme in their difference between high and low tide. This occurs when the Sun, Moon, and Earth are more or less aligned, and thus the gravitational pull of the Sun and Moon are “added”, creating higher high tides and lower low tides. Neap tides refers to when the Sun and Moon are at right angles to each other, canceling out each others pull a little bit, creating a lower high tide and a higher low tide; the tides are less extreme in their differences between each other.
From Chapter 2, we learned about how the zodiac symbols are derived from the constellations that are along the ecliptic. As the Earth orbits around the sun, different constellations are visible. The Babylonians set the zodiac signs over 3,000 years ago in correlation with their 12 month calendar. While we still use the same time frame for determining things such as your zodiac sign, it is no longer accurate. The sky as we see it is different than the sky the Babylonians due to a shift in the Earth’s axis (North Pole). It does not point in the same celestial direction that it once did, so while you might think you are a Sagittarius, you might be a Capricorn instead!
This post serves as a trial to make sure that all is set up and formatted correctly, but I do want to include something fun! Below is a picture of the Milky Way Galaxy (the same picture we used in class). I really enjoyed the last lecture because it made me realize just now massive the universe is and how small I am in the grander scheme of things. It was incredibly humbling.