What is the rotation of the earth? Is it clockwise or anti-clockwise?
When viewed looking down on the north pole from above, the Earth rotates anticlockwise. This is the definition of a north pole; when viewed from above the south pole, it rotates clockwise. These definitions ensure that the sun always rises in the east & sets in the west, no matter what planet you are on. Naturally, it has nothing to do with any magnetic field. Direction of rotation is viewer-dependent; a flat spinning disk rotates clockwise or anticlockwise according to which side one is observing.
How did the Ptolemaic model explain retrograde motion of the planets?
When we observe the other planets from Earth, as we watch them throughout the year - or longer - they sometimes appear to move backwards in the sky instead of their normal forwards motion. During this time, the planet in question is said to be in retrograde. Ptolemy held the Earth as the center of our Solar System. To correct for seeing planets in retrograde, he came up with the idea of epicycles. Planets which not only travel around in a circle about Earth, but in a circle around the circle. This can be seen in this diagram. http://www.polaris.iastate.edu/EveningSt... We must note that the use of epicycles did not solve Ptolemy's problem as the predicted motion of the planets into future dates failed to place the planet where it was actually seen.
A ___ model explained the apparent backward motion of planets?
Ptolemy's model (with epicycles and deferents) was the best model known for predicting the positions of planets for about 1400 years, until Kepler's work with elliptical orbits produced better results. I'm sure the "desired" answer is "heliocentric" but Ptolemy's model also explained the apparent backward motion. His model was as it was because he did not know how to do the math for other than circular motion. Kopernik (a Pole, whom we call Copernicus) developed his heliocentric model which explains the apparent backward motion more clearly, but its predictions of planetary positions were not as good as Ptolemy's, until Kepler developed his laws of planetary motion.
Which solar system planets do Rahu and Ketu represent in Vedic astrology?
I am very pleased with this question. It is very important to understand what these grahas are and what they represent and how they influence us.First of all I am very grateful to my Jyotish Guru Ji, who beautifully and scientifically explain the grahas as per Graha Guna Swarupa Adhyaya given in Brhat Parasara Hora Sastra.Let us understand what a graha (planet) is? Graha is from the word Grahana which means eclipse. Planets eclipse our mind so control our destiny as all our actions and their reactions.The planetary schemes that was given by Maharsi Parashar:SuryaChandraMangalBudhaSukraGuruShaniRahuKetuPeople may ask why these planets are chosen and why actual planets like Neptune, Uranus and Pluto were ignored.Maharshi Parashar clearly states that we have to take geocentric view not helio centric, and the motion of the Earth will be assigned to Sun. Now we are very clear that the motion of the sun is actually an apparent motion.Second question is that why moon is taken as a planet and planets after Saturn as disregarded. The seven physical planets actually denote seven spectrum of light (VIBYOR) and planets after Saturn are so far that their light cannot influence us. That is why they are disregarded and moon which shines above us is taken into account.Lastly what is Rahu and Ketu. Rahu and Ketu are actually two nodes of Moon. Rahu is north node and ketu is south node. All the planets are have nodes, and they do influence us. If Rahu and Ketu are not physical planets then why there are taken. Rahu and Ketu are shadow planets, they don't have physical body but they do have light. There some lights that we cannot see but the do affects us. These lights are ultraviolet and infrared, human eye cannot see it but it does affect our minds in a big deal.This why Rahu and Ketu is very important. This explanation is not given any book. This is knowledge of tradition, which only a guru can impart to its students.
If a planet is 500 light years away, does that mean that even if you traveled at the speed of light, it would still take you 500 years to get there?
First of all, it is not possible for a real object to travel at the speed of light. But for the sake of the question, let us discuss two scenarios:Traveling near the speed of light (Non-fictional scenario)Let us assume we are not traveling at the speed of light, but near the speed of light. This is theoretically possible.For the people of earth, you will reach there after a little more than 500 years have passed on earth.But due to time dilation (time slows down as you move faster), you will experience less time than 500 years.Yes, space and time are entangled in such a way that we pass through both. But the more you move through space (ie. the faster you move), the less you pass through time. This phenomenon is called time dilation. In short, the faster you move, the less time you experience.If you want to experience time dilation by a factor of 500, you will have to travel at about 99.999% the speed of light (my calculator shows 99.9989999%). In that case, you will arrive at your destination in one year. Not just the clocks on your spaceship will show one year, but everything in your spaceship (including you) will have aged by one year when you reach that planet. You will have the same number of heartbeats, breaths, pulses, etc as you would normally have in a year.Traveling at the speed of light (Fictional scenario)To travel at light speed, let’s say we achieve a way to convert all of our mass into energy (probably by some futuristic technology based on nuclear reaction) and travel as mass-less particles (photons) at the speed of light.Then, for the people of earth, you will reach there when 500 years have passed on earth.But due to time dilation, you will experience zero time. You will reach there instantaneously.Once again, the faster you move, the less time you experience. Only now you are traveling at the speed of light.And moving faster has a limit (the speed of light). On reaching that speed (which is impossible for an object with mass), you will no longer pass through time. This is infinite time dilation.TLDR: For people of earth, 500 years will have gone, but for you, you just started and end up at the destination, instantly.
When earth rotates by itself why does the water in oceans, seas, lakes never spills out of its boundaries?
Take large bowl and fill it with water. Now, walk forward with the bowl in your hand, steadily increasing your speed, but being careful to keep the bowl level. Notice how the water stays in the bowl and at the same level? The water moves with the bowl.The same is true of the water on the surface of the planet. It moves at basically the same speed (ignoring tidal effects) as the surface upon which it sits. Not only does the Earth spin but it also orbits the Sun, and the water maintains its level(s) on the planet it is a part of. You are also spinning along with the Earth at the same time you are speeding around the Sun.Now, if the Earth suddenly stopped spinning, the water would continue to move and there would be a great deal of sloshing (but no one would witness it because everything else, including every frail human body, would also continue to try to keep moving and we would all be torn apart by impacts with other objects).Gravity is what holds the water on the surface of the planet, it is what curves the surface of the oceans to match the curvature of the Earth.
In which direction does Earth rotate?
The way humans have categorized the direction of the Earth’s rotation, is in a West to East motion.Or “left-to-right” if you will.Why does it spin in a Eastward motion?Because humans are lazy.Explaining further, imagine that the Earth spins on an axis (which it does btw):The blue and green smaller lines are actually the same line (it goes into the Earth on one end and comes out the other).Humans have categorized the North Pole to be at latitude 90 degrees, and all longitudinal lines meet there.The South Pole is at the exact opposite location, on the other side of Earth (latitude is 90 degrees south, and longitudinal lines meet there).Geographers use the North Pole as a symbol for “North” and the South Pole as a symbol for “South”.Therefore, West is leftward and East is rightward.Since the Earth naturally travels in a West to East motion, the Earth’s rotation is said to be moving “Eastward”.The only reason we don’t say it’s moving in the opposite direction, is because of its convenience to us.If humans had originally felt like the South Pole should be called the North Pole instead (now “North”), we would say the Earth is rotating in a Westward motion.If you are confused about why the Earth has to spin Eastward, that’s a different story.Back when solar systems formed from clouds, molecules were moving in different directions. This was somewhat spontaneous, as there probably wasn’t a perfect balance in velocities (probably a net velocity in some direction). This ends up providing the angular momentum for the system itself, which ends up being conserved (it is in a “closed system”).Imagine an ice skater, when they pull their hands in when spinning, they end up spinning faster. The same can be said for the formation of stars and planets. As gravity will cause the cloud to condense and shrink in size, it ends up becoming faster in order to maintain the angular momentum. So over time, as the cloud condenses the net velocity becomes more and more notable.Another side effect of the cloud itself spinning faster is the faster it spins, the more stables it becomes upon itself. Much like a top spinning and balancing itself at its highest speed.The Earth (and other planets follow this same rule), the smaller the cloud becomes, the more stable the spin axis.However, if another object (i.e. planet or cosmic object) were to collide and offset the rotational direction, the direction could very well change (as with Venus & Uranus).RAKEESH S. KUMAR
Why do ocean currents in the northern hemisphere move in a clockwise direction while currents in the southern hemisphere move in a counterclockwise direction?
The earth rotates on its axis from west to east. This rotation causes both the wind and ocean currents to move from east to west. Thus, the wind movement and ocean currents in the northern hemisphere goes clockwise and counter clockwise in the southern hemisphere. Because Earth rotates on its axis from west towards the east, air near the surface from the tropics is moved toward a westerly direction (toward the right as it is often called) in the northern hemisphere. Notice the difference between the lines drawn when the globe did not move (shown with arrow heads) and the lines which were drawn as Earth rotated. The Coriolis Effect also causes ocean surface currents to be deflected to the right of the winds. At the equator, there is no Coriolis Effect so there is very little to no deflection. At other latitudes, each layer of water (depth) is set into motion by the Coriolis Effect. Each layer moves at different velocities and moves to the right until (if you were to look from above), a spiral shape of ocean currents would form.As seen in the diagram at the right, adding each of these directions together produces a net current of flow which is perpendicular to the wind (within about the top 100 meters of ocean water). This phenomenon causes currents in the northern hemisphere to move in a clockwise direction and a counterclockwise direction in the southern hemisphere. If there were no continents or island land masses, each of the ocean currents would have either an easterly or westerly flow.