Is there an analogy between planets orbiting the sun and electrons orbiting the nucleus in an atom?
The term “atomic orbital” has its origins in an analogy with planetary orbits, but it is misleading terminology. The breakdown of this analogy, i.e., the failure of classical physics to describe the motion of the electron around the nucleus in analogy to planetary orbits, is part of the crisis that culminated in quantum theory.Here’s the analogy: both the solar system and the atom are systems with a central object about which relatively smaller objects move under the influence of an attractive Inverse-square law. But the straightforward application of classical physics to the atom did not provide self-consistent results, or results that reproduced basic properties of atoms (such as the fact that they are stable). In the Bohr model, and its extensions by Arnold Sommerfeld, the electrons were viewed as following orbits, but with certain quantum conditions imposed upon them. This model explained some of the properties of atoms, such as spectral emission lines, but was not a complete and self-consistent theory. With the advent of quantum mechanics, the electron trajectories were abandoned completely, but the term “orbital” remained.The term "orbital" in the quantum theory of the atom does not correspond to a definite path or trajectory, as it does in the orbital mechanics of the solar system. An atomic orbital is a complex-valued function whose square is a probability distribution of the electron's probable position. Here are images of some atomic orbitals of Hydrogen:
How does Tatooine have two suns?
The answer is three fold becasue the question can be viewed for so many angles.First, they are there due to an optical illusion that exposed two suns on the film when Star Wars was first shot. The effect just ‘fit’ so Lucas kept it.Second, in reality binary and trinary systems are very common. In fact they outnumber single star systems (at least here in the Milky Way).Binary StarsLast, I’ll keep saying this until people get it, Star Wars is not sci-fi despite its setting in space and the presence of many sci-fi trappings. Star War is a fantasy set in space.Rod Serling once pointed out the difference: “Science fiction is the improbable made possible, and fantasy is the impossible made probable.” In other words fantasy is made up and you can throw 2, 3 , or 4 suns in the sky without regard for how the heck it would work mechanically. Animals that could never fly (let alone exist) in reality, like dragons, can happen. In sci-fi writers need to try and confine themselves things that are at least theoretically possible. All that is to say that Lucas did not care about the science of it, there was an optical illusion, it looked cool and it fit a desert world so he kept it.
What are some of the amazing photographs taken from mobile phones?
This answer is dedicated to all those people who spend on DSLRs just to get good pictures and who say that good photos cannot be got on a phone or point and shoots."Beauty lies in the eye of the beholder, not on the gear used" :)Taken when I was exiting my office. It is a little edited.2. Taken during a Tea break at office. No much editing except the tone and shadow.3. Taken at Mysore from a moving vehicle. Changed the tone and temperature.4. This does not have any filters added. The exposure was reduced to get this image.5. My first picture taken on a Nokia phone without any filters or editing.6. On my way to goa somewhere between Goa and Karwar. Slightly edited.7. This also does not have any filters added to it. The exposure was reduced to capture the natural sunrise.8. This is the sunset captured at Gokarna. Again no filters added except the exposure reduction.9. This is again from Gokarna. Have edited by adding a little center light and blurring the edges.10. Taken at Gokarna, where the picture was made B&W in postediting.11. Center light and a light shadow at the corners. 12. During the rainy season,headed out into the garden with an umbrella to capture this shot.Edit 1: Changed "This answer is dedicated to all those people who spend on DSLRs for better pictures." to "This answer is dedicated to all those people who spend on DSLRs just to get good pictures and who say that good photos cannot be got on a phone or point and shoots."No offense to the people who own DSLRs as well.
How did Galileo come up with the theory that the Earth revolved around the sun?
Heliocentrism (the idea that the Earth revolves around the sun) is usually attributed to the Polish astronomer Nicolaus Copernicus, and refined by Johannes Kepler. Aristarchus proposed a heliocentric system around 270 B.C., and various others doubted the geocentric (earth-centered) model before Copernicus.Ptolemy's system was complex. Occasionally planets exhibit "retrograde" motion: they appear to reverse directions against the background of stars. Ptolemy's explanation of this phenomena was this motion was real, and caused by the planets moving in "epicycles" around a deferent circle. It turns out that you can match the motion of the planets pretty well by such a mathematical model (at least, the motion as measured by the naked eye) even though the actual motion of the planets doesn't have that form. Copernicus elaborated the heliocentric model in his work De Revolutionibus in 1543. Copernicus argued that the apparent retrograde motion of planets wasn't real, but caused by a parallax effect: as the Earth passed Mars in its orbit, the apparent position of Mars would appear to back up, the same way that a car on the highway seems to back up when you pass it at a faster speed. Copernicus showed that the complex system of epicycles wasn't necessary: you could compute the past and future positions of the planets with his new model. But there was no real evidence to suggest that it was actually true instead of geocentrism (except perhaps for Occam's Razor). Until Galileo.Galileo was one of the first observational astronomers who had access to the newly invented telescope. He made observations of both Jupiter and Venus, and published The Starry Messenger in 1610. What he discovered was that like the moon, Venus exhibited a full range of crescent phases, an observation which was not consistent with geocentrism, but was consistent with heliocentrism. Similarly, while observing Jupiter, he found four previously undiscovered moons which were obviously orbiting Jupiter. Certainly if those bodies could circle Jupiter, it was support of at least the idea that bodies could orbit bodies other than the Earth.The Catholic Church was not happy with this notion, and placed Galileo under house arrest for the remainder of his life for expressing these ideas.Isaac Newton formulated his theory of gravitation and published it in 1687, and that marked the end of heliocentrism.The Wikipedia page has some good links.Heliocentrism
Do we know if the sun revolves around something else?
Technically, Earth Does Not Orbit Around the SunThe discovery that Earth revolves around the Sun was revolutionary. It fundamentally changed how we viewed the cosmos, as well as ourselves.But the Earth does not revolve around the Sun. At least, not exactly. Time to get pedantic."Technically, what is going on is that the Earth, Sun and all the planets are orbiting around the center of mass of the solar system," writes Cathy Jordan, a Cornell University Ask an Astronomer contributor."The center of mass of our solar system very close to the Sun itself, but not exactly at the Sun's center."Every single object in the solar system, from the gargantuan sun to the tiniest speck, exerts a gravitational pull on everything else. The solar system is basically a massive game of tug of war, and all of the yanking balances out at a specific point: the center of mass, or "barycenter." Everything in the solar system orbits around that point. Sometimes, it's almost smack dab at the Sun's center. Right now, the barycenter is just outside the Sun's surface. But it's constantly changing depending upon where the planets are in their orbital paths. Because the Sun holds 99.87% of all the mass in the solar system, it's always going to win the tug of war. Even if all the planets were perfectly lined up on one side of the Sun, the center of mass would be just 800,000 kilometers off the surface of the Sun. That sounds like a lot, but remember, our solar system is big! Such a barycenter would be roughly 70 times closer to the Sun than the closest planet to the Sun, Mercury. An even better illustration for center of mass is the binary star system. When two stars of comparable mass cohabit the same corner of space, they orbit about a point between each other. However, rather than play a billion-year game of cosmic tag, more often than not, binary stars will take an elliptical orbit! The rest of the universe certainly doesn't revolve around the Earth, but, like so many topics in science, it's an oversimplification to say that everything orbits around the Sun.