# Planet Earth

## Earth is the planet where we live. It is the third planet from the Sun and is currently the only known planet in the Universe that is able to support life.

### How far is the Moon from the Earth? A lunar distance (LD) is an astronomical measurement of the distance from the Earth to the Moon. The average distance from Earth to the Moon is 384,403 kilometers or 238,857 miles, but the actual distance varies over the course of the orbit of the moon. Depending on the Moon's location in its orbit, it is between 225,623 and 252,088 miles away from Earth. This is about 30 times the diameter of the Earth. Measurements of the lunar distance are made by measuring the time it takes for light to travel between the LIDAR stations on Earth and the retroreflectors placed on the Moon. Experiments show that the Moon is spiraling away from Earth at an average rate of 3.8 cm per year. Orbital distances are calculated between the center of the Earth and the center of the Moon. So the actual surface-to-surface distance is shorter by about 7457 kilometers (4634 miles). Because tides spin faster than the Moon moves, the tidal reaction pulls the Moon forward a tiny bit. The moon recedes at a rate of approximately 3.8 cm (1.5 inches) per year. When there was only one continent, the rate was less. . The moon is on an elliptical orbit, so it it not consistently the same distance from earth. When the moon is the closest to earth, it is 225,623 miles away; when the moon is farthest away from earth, it is 252,088 miles away.

### How do you live happily in this tough world? ### Does the discovery of life on other planets contradict with religions? ### What is the circumference of the Earth? The equatorial circumference of the Earth is about 40,075 km (24,901 m). The polar circumference of the Earth is about 40,008 km (24,860 m). More Precisely: Earth is not a perfect sphere, but is "flattened" at the poles. Its shape is described as an oblate spheroid. So, the Earth's circumference is about 68 km (41 m), larger around its belly than around its poles. This difference is small enough that, were the earth shrunk down to the size of a billiard ball, it would be more perfectly round than most billiard balls. Caveat: The numbers for circumference are always approximations because Earth's surface is irregular and constantly changing. The tidal bulging (constantly shifting) is a dynamic factor. Polar measurements vary with longitude. So these approximations can differ by a kilometer or two.

### How much time would taken by sun rays to get to the sun from the earth? The Earth is, on average, about 93,000,000 miles from the Sun, and light travels at 186,000 miles per second. Divide one number by the other, and you see that light takes almost exactly 500 seconds to reach the Earth. That's 8 minutes 20 seconds. The Earth's orbit is an ellipse; sometimes a little closer, sometimes a little farther away. Minor comment: That answer doesn't exactly fit the question, but it's pretty obvious it's answering what the question probably meant.

### What is the ring around the earth called? The atmosphere. Space junk, or space debris, and there are tons of it left behind from countless missions. It causes problems for current missions, since collisions could result in serious damage or death.

### Where do the direct rays of the sun strike earth when the sun is at it lowest point in your sky? For those living in the Northern Hemisphere the sun's direct rays would be falling on the Tropic of Capricorn when the sun is at the lowest point in your sky. For those in the Southern Hemisphere it would be on the Tropic of Cancer.

### In perihelion what will be the effect to earth rotation and revolution? "Perihelion" is the point in the earth's path around the sun where the distance between the two is minimum, that is, where the earth is closest to the sun. We reach that point and pass it each year around January 2. That event has no effect on the earth's rotation, and doesn't influence the length of daylight and dark. Since the earth's orbital speed is greatest at that point, it does travel a slightly greater angular portion of its orbit on that day than the average. To earthbound observers, the effect of this is that the sun appears to travel a greater distance across the background stars, or through the "Zodiac" if you will.

### What is the communication delay between earth and mars? Given the following approximate radii for Earth and mars orbits: Earth = 149,598,261 km Mars = 227,939,150 km The shortest distance between the two is the difference between the two, which yields 4minutes 21seconds for radio to go that distance. The longest distance between the two is the sum, which yields 21minutes.

### What are cool things to see on Google Earth? There are so many cool things to see in Google Earth from airplanes caught by satellite in mid-flight, bizarre land formations, crop circles, to extraordinary and strange places. Not to mention sights in Street View, Mars, Moon, Sky View, and under the ocean. In related links you'll find some useful places to check out the many cool things already found in Google Earth.

### How far is the Earth from the Sun? The exact distance between Earth and the Sun varies with its position in its orbit, which is elliptical. The average distance (the mean distance) between the Earth and the Sun is about 150 million kilometers (93 million miles). The average distance from the Earth to the Sun is also called 1 astronomical unit (or AU). This is established as 149, 597, 870.7 kilometers (92,955,887.6 miles). Aphelion (when the Earth is the farthest from the Sun) occurs around the first week of July. The distance is about 152 million km (94.4 million miles). Perihelion (when the Earth is closest to the Sun) occurs in the first week of January. The distance is about 147 million km (91.3 million miles).

### What is after a trillion? Quadrillion(15) After it: quintillion(18), sextillion(21), septillion(24), octillion(27), nonillion(30), decillion(33)

### When is the world going to end? ### What is the weight of the Earth? Weight of the Earth The Earth is in orbit around the Sun, or in freefall, so technically its weight is zero. Weight depends on measuring the attraction between two objects, such as a person and the Earth. It is actually a mutual attraction between their masses. The mass of the Earth, however, can be calculated from its gravity. Mass of the Earth Newton showed that, for spherical objects, you can make the simplifying assumption that all of the object's mass is concentrated at the center of the sphere. The following equation expresses the gravitational attraction that two spherical objects have on one another: F = G * M1 * M2 / R2 R is the distance separating the two objects. G is a constant that is 6.67259x10-11m3/s2 kg. M1 and M2 are the two masses that are attracting each other. F is the force of attraction between them. Assume that Earth is one of the masses (M1) and a 1-kg sphere is the other (M2). The force between them is 9.8 kg*m/s2 -- we can calculate this force by dropping the 1-kg sphere and measuring the acceleration that the Earth's gravitational field applies to it (9.8 m/s2). The radius of the Earth is 6,400,000 meters (6,999,125 yards). If you plug all of these values in and solve for M1, you find that the mass of the Earth is 6,000,000,000,000,000,000,000,000 kilograms (6 x 1024 kilograms), or 6 quintillion metric tons (6 x 1021 tonnes). ---- As odd as it sounds, the weight of Earth is exactly zero, because the Earth is in orbit around the sun, and as such, the Earth is free falling in space around the sun.1 Any object in free fall in space, including an object in orbit, is weightless. That is why astronauts are weightless when in orbit around the Earth. Weight is a characteristic of an object as it relates to the gravitational field it is resting in. You would have to take the earth to a much more massive world, like Jupiter, and ignoring the difficulties caused by the gaseous make up of the planet, put the Earth on a rather large scale to see what the Earth "weighs" there. Of course, its weight would change based on its distance from the center of gravity of the attracting object. On Earth, weight changes negligibly at any altitude within the atmosphere. The mass of the earth is another matter. The mass of the earth is 5.9736×1024 kg, or about 5,973,600,000,000,000,000,000,000 Kg. 1 An orbit is a special case of a free fall condition. As the orbiting object falls downwards, it also travels transversely (sideways) at such a rate that its falling trajectory projects a curve that always remains the same distance from the planet's surface. ====================================== From a different perspective: The following experient was performed. Gravitational forces always occur in pairs, between the centers of two masses, and the two forces are equal, so that the force between me and the earth is what I call my "weight". If this is generally correct, then the weight of any object depends on the other object to which it is gravitationally attracted at the moment, and if that's true, then I can weigh the earth on me. In my laboratory, I placed a tiny mirror on the floor. I then took a bathroom scale out of a cabinet, inverted it, and placed it top-down on the floor, with its digital display visible in the tiny mirror. I then alighted upon the scale, placing my full body upon the surface that is normally the bottom of the scale ... the surface with the label, the rubber feet, and the battery door on it. In this way, I was able to weigh the earth in my gravitational field, and (just as Sir Isaac might have predicted) it was precisely equal to my weight when measured in the earth's gravitational field. It would seem that in order to accurately quote the earth's weight, the question must specify the other object to which the earth is being gravitationally attracted, and must also specify the other object's mass, and the distance between the centers of mass of the earth and the other object. As any of these details changes, so too does the earth's 'weight' change!

### Where do most earthquakes occur in the world? Most earthquakes occur along the edge of the oceanic and continental plates. The earth's crust is made up of several pieces, called plates. The plates under the oceans are called oceanic plates and the rest which are under the land surface are continental plates. The plates are moved around by the motion of a deeper part of the earth (the mantle) that lies underneath the crust. These plates are always bumping into each other, pulling away from each other, or past each other. The plates usually move at about the same speed that your fingernails grow. Earthquakes usually occur where two plates are running into each other or sliding past each other. Earthquakes mostly occur in places where there is a Fault Line. Plates under the Earth's surface move and push against each other. Some of these places are: South America North America Japan Australia Africa Philippines India Caribbean Haiti Alaska is the most earthquake-prone state and one of the most seismically active regions in the world. Alaska experiences a magnitude 7 earthquake almost every year, and a magnitude 8 or greater earthquake on average every 14 years. or just this near subduction zones.

### How far from Earth is Jupiter? Because both planets orbit the sun, the distance varies, since at some times both will be on the same side of the sun, but at other times, on opposite sides. When Jupiter and Earth are closest, Jupiter is 390,682,810 miles (628,743,036 km) from Earth. The Earth is 93,000,000 miles (149,668,992 km) from the Sun. Jupiter is 483,682,810 miles (778,412,028 km) from the Sun. At our most distant, Jupiter is 576,682,810 miles (928,081,020 km) from the Earth, when the two planets are on opposite sides of the Sun. Measured in Astronomical Units (AU), the distance between Earth and Jupiter varies from 4.2 AU to 6.2 AU. An Astronomical Unit is approximately 93,000,000 miles (149,668,992 km), or the mean distance from the Earth to the Sun. Therefore, the distance between the Earth and Jupiter can be anywhere between slightly over four times or six times the distance from the Earth to the Sun. The calculations are very close, but approximate, and also depend upon the slightly varying mass of the Sun, which has an effect on orbital distances. 