Formation Theories
Big Bang Theory
13.8 billion years ago there was a rapid expansion of energy from a singularity. We don't know why it happened and we don't know exactly what happened at the very moment it started, but we have a pretty good idea of what the universe looked like tiny fractions of a second after it began. This is the Big Bang Theory. The name itself was meant to be derogatory or an insult. It was never meant to be a description. A famous astrophysicist in the 1940s called it this mockingly on a radio show and the name stuck. It, however, was not a bang. There is no sound in space because the atoms are too far apart to vibrate and carry sound effectively. Also, keep in mind that, at the beginning, there was nothing...no atoms, no space, no gravity, no time, nothing. Well, nothing except a singularity of infinite energy. Immediately after the expansion began, the energy started cooling and forming protons and electrons and then hydrogen. Through a wonderful stroke of luck, gravity took over and squeezed stuff together and formed stars. These early stars lived short, violent lives and blew up; spreading many new elements throughout the cosmos. We'll talk more about stars on the next page.
How do we know that this happened? Red shift. When things move toward you, sound becomes higher pitched and the wavelength shortens. In the visible light, shortened wavelength is moving toward the blue end of the electromagnetic spectrum: blue shift. When the object moves away from you, the wavelength becomes longer and moves toward the red end: red shift. When we look at the spectral lines of stars and galaxies, we see that they are red shifting. That means they are all moving away from each other. That implies expansion. Condense it back to when they were all together and it's a common point...a common beginning. Edwin Hubble was the first to apply this concept (known as a Doppler Shift) to the stars and figure out what was happening. That lead to more discoveries providing more evidence for this theory. An accident provided a huge piece of the puzzle. Some technicians in New Jersey were trying to monitor radio and telephone signals with a large satellite dish. They kept finding static in the background. It was finally determined that what they were hearing was background microwave radiation left over from the Big Bang.
13.8 billion years ago there was a rapid expansion of energy from a singularity. We don't know why it happened and we don't know exactly what happened at the very moment it started, but we have a pretty good idea of what the universe looked like tiny fractions of a second after it began. This is the Big Bang Theory. The name itself was meant to be derogatory or an insult. It was never meant to be a description. A famous astrophysicist in the 1940s called it this mockingly on a radio show and the name stuck. It, however, was not a bang. There is no sound in space because the atoms are too far apart to vibrate and carry sound effectively. Also, keep in mind that, at the beginning, there was nothing...no atoms, no space, no gravity, no time, nothing. Well, nothing except a singularity of infinite energy. Immediately after the expansion began, the energy started cooling and forming protons and electrons and then hydrogen. Through a wonderful stroke of luck, gravity took over and squeezed stuff together and formed stars. These early stars lived short, violent lives and blew up; spreading many new elements throughout the cosmos. We'll talk more about stars on the next page.
How do we know that this happened? Red shift. When things move toward you, sound becomes higher pitched and the wavelength shortens. In the visible light, shortened wavelength is moving toward the blue end of the electromagnetic spectrum: blue shift. When the object moves away from you, the wavelength becomes longer and moves toward the red end: red shift. When we look at the spectral lines of stars and galaxies, we see that they are red shifting. That means they are all moving away from each other. That implies expansion. Condense it back to when they were all together and it's a common point...a common beginning. Edwin Hubble was the first to apply this concept (known as a Doppler Shift) to the stars and figure out what was happening. That lead to more discoveries providing more evidence for this theory. An accident provided a huge piece of the puzzle. Some technicians in New Jersey were trying to monitor radio and telephone signals with a large satellite dish. They kept finding static in the background. It was finally determined that what they were hearing was background microwave radiation left over from the Big Bang.
Nebular Theory
The Nebular Theory (also called Solar Nebula Theory) is an explanation of how solar systems form. This theory has been around since the 1750s. And it still explains how our Solar System formed (with a few modifications). I break this theory down into 4 steps:
1. A cloud of gas and dust (nebula) collapses due to gravity.
2. The collapsing cloud starts spinning (angular momentum).
3. The spinning cloud forms a thin disk around a central mass.
4. Planets form from cooling dust and ice particles smashing together, while the central mass becomes a star.
With this theory, our Solar System makes sense. The inner planets are rocky and dense and the outer planets are gaseous and light. The Kuiper Belt is explained as debris blown out there by shockwaves from the Sun as it began fusion. The Asteroid Belt is explained as a failed planet between Mars and Jupiter that Jupiter's gravity wouldn't allow to form. Everything seems to fit. The problems started up in the 1990s when we found our first exoplanet (a planet beyond our Solar System). Gas giants should (according to the Nebular Theory) be far away from the star. But we began finding a lot of gas giants right next to stars...closer than Mercury is to the Sun. That shouldn't happen, but that's what we're finding. Does this mean that the Nebular Theory is bad? No. It just needs to be modified to fit the new data. If it cannot, then it's probably bad. But it's held up just fine until now.
The Nebular Theory (also called Solar Nebula Theory) is an explanation of how solar systems form. This theory has been around since the 1750s. And it still explains how our Solar System formed (with a few modifications). I break this theory down into 4 steps:
1. A cloud of gas and dust (nebula) collapses due to gravity.
2. The collapsing cloud starts spinning (angular momentum).
3. The spinning cloud forms a thin disk around a central mass.
4. Planets form from cooling dust and ice particles smashing together, while the central mass becomes a star.
With this theory, our Solar System makes sense. The inner planets are rocky and dense and the outer planets are gaseous and light. The Kuiper Belt is explained as debris blown out there by shockwaves from the Sun as it began fusion. The Asteroid Belt is explained as a failed planet between Mars and Jupiter that Jupiter's gravity wouldn't allow to form. Everything seems to fit. The problems started up in the 1990s when we found our first exoplanet (a planet beyond our Solar System). Gas giants should (according to the Nebular Theory) be far away from the star. But we began finding a lot of gas giants right next to stars...closer than Mercury is to the Sun. That shouldn't happen, but that's what we're finding. Does this mean that the Nebular Theory is bad? No. It just needs to be modified to fit the new data. If it cannot, then it's probably bad. But it's held up just fine until now.