Earths orbit refers to the path of the earth around the sunEccentricityA small ellipse whoseSemimajor axis（a）1.496×10eightKilometers;Semi stub shaft（b）1.4958×10eightKilometers;Half focal length（c）25×10fiveKilometers;Perimeter (l) 9.4 × 10eightKm.earthElliptical orbitEccentricity (e) andOblateness(f) (1/60 or 0.016 and 1/298.25) respectively, the sun is at one focus of the ellipse.The distance from the earth to the sun varies by 1.471 × 10eight～1.521×10eightKm, the average distance is 1.496 × 10eightKm.The plane of the earth's orbit isEcliptic surface。
SolarTidal forceThe role of,Earth revolutionThe kinetic energy will be gradually transformed intoTidal energy。In a long term, the earth will gradually move away from the sun, but this speed will be very small.A smaller factor is the expansion of the universe, but at this stage,Cosmic expansionIt has played a smaller role and is still ignored compared with the small figure above.The effect of these two factors is long-term, and it may be seen from this short-term range that neither of these two factors has played a minor roleMeteoroid(It is a meteor) The impact on the earth plays a big role.However, the Earth's orbit will not change much in the course of billions of years at most, but there will be, and it will affect climate change.
Because the elliptical orbit is a compromise of the Earth's gravity on nearby celestial bodies.A system with only one planet and one star is meaningless.During the formation of the early solar system, the primitive planets wereasteroidAnd a series of other disturbancesElliptical orbitFormation of.This is called the theory of planetary migration.
First of all, a perfectly circular orbit is also a kind of elliptical orbit, which is just a special elliptical orbit.
If the conditions for the earth to operate in a perfectly circular orbit are very harsh, the other planets of the sun must first disappear, and then the stars close to the sun must also disappear, otherwise they will have an impact on the earth and lead to the change of the earth's orbit.
The earth revolves around the sunUnder the condition of given energy, there are countless possible orbits,Circular orbitJust one of them.If you want the earth to move in a perfectly circular orbit, the energy and momentum of the earth must meet certain conditions.Is the kinetic energy Ek andpotential energyThe relationship of Ep satisfies Ek=- Ep/2.Or when Ek=- EP/2,Earth movementThe direction is perpendicular to the sun earth line.This condition is very harsh. Even if the earth moves in a circular orbit, a small disturbance can change this state, making the earth move in a new elliptical orbit.
Go further and further
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The Spanish monthly magazine Fun published the article "Pieces of Misalignment" in 2018 by Miguel Angel Sabadel.According to the article, some people in the scientific communitydark substanceorDark energyThe behavior of these ghost entities is criticized, but if the existence of these ghost entities is not assumed,General relativityThere was no explanation.Maybe we should modify or even use newGravitational theoryTo replace Einstein's general theory of relativity.
The distance between the earth and the sun is increasing for unknown reasons
According to the article, when astronomers determine thatAstronomical unit(AU).The astronomical unit isLength unit，Approximately equal toThe average distance between the earth and the sun,Error rangeIt is between 1m and 10m, so we can use an exact 12 digit number to determine its value (1AU=149597870700m).howeverJPLResearcher Erlan Miles Standish pointed out in 2004 that AU seemed to increase over time.In the same year,St.Petersburgpractical astronomy Two scientists of the Institute have checked more than 200000 observation data and found that the seemingly stable AU per 100Annual increase15m.2005Russian Academy of SciencesScientific researchersYelena Pityeva released a more detailed analysis, including 317000 records from 1913 to 2003. The results show that the distance between AU and each century is about 7 meters.
measuring method
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Earliestancient GreekAlistarks oflunar eclipsePassing over the moon from time to timeGround shadowAndMoonRelative size of, usinggeometryMethod, calculate the distance from the earth to the moon in terms of the diameter of the earth.Later in ancient GreeceHipparchus Using the same method, we can getMoon distanceIs 30 times the diameter of the earth, andAncient EgyptOfEratoceniAccording to the change of the included angle of the noon shadow at the summer solstice between different latitudes and the distance between different latitudes, the earth is calculatedmeridianThe length ofEarth Moon Distance。Reusetrigonometric function, we getSun earth distance。
In about 5 billion years, the sun will begin to slowly transform into an expandingRed Giant。Its outer gas will continue to expand, and its volume and brightness will reachMaximumAt that time, the sun will engulf the whole earth.How can we avoid being scorched by the sun?
But in the 1.1 billion years before that, the brightness of the sun will increase by 11%, and the average land temperature will rise to about 50centigrade(120Fahrenheit degree)。The ocean heats up,Marine waterIt's like being in a sunny kitchencooking benchA pot of water on the water is slowly evaporated without boiling.Plants and animals will be difficult to adapt to this greenhouse environment, but some are calledArchaeaSingle cell ofOrganismWill survive.
But soon, onceWater vaporget intoatmosphere, from the sunultraviolet raysWill result inwaterMolecules split, and the hydrogen needed to form living cells will slowly leak into space.If our descendants or other intelligences after usLife formsTo survive, they must move elsewhere.But where are they going to emigrate?And how can we move there?
One possible way would be to use rockets to migrate to other planets.However, to transport 6.7 billion people, it is equivalent to launching 1 billion aircraftspace shuttle。Even if we can launch 1000 space shuttles in one day, it will take 2700 years to send all the people on the earth away.When people arrive at the new station, they will encounter trouble in life.To move to other planets, these planets need to be earthed in order to provide food, water and oxygen for the life of earth migrants.So why can't we immigrate with the earth?
satellitetracking systemBasic physics tells us that we can actually move planets.When a rocket is launched into space, it producesRecoil forceIt will push the earth in the opposite direction, although the distance of pushing is very small, which is like the gun will fall back after shooting.
Science fiction writer and trained physicist Stanley Schmidt adopted this fact in his novel Father of Evil.This noveldescribeThe aliens areearthantarcticA huge rocket engine was installed to propel the earth.However, the earth in real life is very large, and a rocket has almost no effect on its movement.Launching 1 billion 10 ton rockets in the right direction is only possible to change the speed of the earth by 20 nanometers per second.
Some astronomers have begun to solve the problem of moving planets, but this is not to deal with what happens in human timeEmergency。Santa Cruz University of CaliforniaGreg Rawling of, in fact, they are designing an experiment to understand the dynamics of planetary systems through this experiment.
Laurin and his colleague Dan Krikinski, andUniversity of MichiganFred Adam, an astronomerPlanetary systemThey began to solve the problem of how to push the earth so as not to let the warming sun "steam" it.
In order to achieve the expected purpose, the three of them chose the final destination of the earth as an orbit. The distance between this orbit and the sun is 1.5 times the distance between the earth's orbit and the sun, which is equivalent to the Mars orbit.In 6.3 billion years, when the sun entersRed GiantAt this stage, its brightness will be 2.2 times. At that time, a planet as far away from the sun will get about the same sunlight as the earth.They said that by changing the distantsolar systemThe orbit of the ice body, let them pass near the earth, and put some of their orbitsenergy transfer To the earth can realize the purpose of promoting the earth.
be locatedNeptuneExternal iceSomatic ringThe celestial bodies inside are calledKuiper belt(Kuiper Belt), a ball formed by a comet farther awaycloud clusterbe calledOort Cloud(Oort cloud?)。Because they are far away from the sun, these celestial bodies have relatively lowOrbital energySo we can use the method specially used to deflect asteroids close to the Earth to push them.These methods range from slight gravitational drag to the use of largepropellerPush hard, it can be said that there are all kinds of things.
Earth Jumping Day
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Satellite tracking system
German artist Rauschman set up the "Jump Earth" site in 2005 to launch the "Jumpearth day”(WorldJumpDay), callwestern hemispherePeople 11:39:13, Greenwich, July 20, 2006（TaipeiAt 19:39:13 on July 20), they jumped into the sky together, saying that as long as 600 million people jumped at the same time, they would be able to change the position of the earth in the universe, even if the earth changed its orbit and left the sun a little, thus "stoppingGlobal warmingExtending daytime hours to create a more livable climate ".
Rauschman first told scientists andBlogPut forward "Jumpearth day”, I only talked about it in the circle of friends, but the news spread and became a global topic. Curious, funny and good people went online and the site was crowded several times.The Qitiao Day is just around the corner. 598104080 people have registered to participate, nearly half of the world's online population.The website claimed that there were 600 million people on the 20th.
It is a kind of "geo engineering" that 600 million people jump out of the orbit synchronously, with good intention, but it is difficult to take it seriously because of many problems.From a moral perspective, who can bear the consequences of the Earth's orbital change?Some people say that the earth has entered a new orbit,calendarDon't you want to rewrite it?Others said, who can guarantee that so many people really take off at the same time?
But the real question is, is this jump really useful?According to "Crazy Physics", which discusses strange ideas.Assuming that each person weighs 100 kilograms, 600 million people will multiply 10, 11 square meters by 6. The kinetic energy generated by their simultaneous jump is equivalent to 7.5 megajoules (TJ), equal to one million tonsDynamite(equivalent to a modernHydrogen bomb）2% of the energy released, causing only one earth displacementhydrogen atomThe radius, that is, the Earth's orbit, remains unchanged.
Celestial objects are coming to the earth orbit silently
The plane where the earth orbits is called the ecliptic plane
bbc(BBC) reported that scientists calculated that the earth could offset the atmosphere if it was 2.4 kilometers away from the suncarbon dioxideDouble the damage, but it requires millions of hydrogen bombs to blow up the earth.Will the earth still be there?
The idea that man can conquer nature has never been broken since ancient times. For example, human beings have never wanted to control or change the climate, and they use greenhouse gases toenvironmentIf you mess it up, you'll get the idea right.Saving the earth has its root cause and symptoms. The root cause is to rapidly reduce or stop the emission of greenhouse gases. It is not easy to see the current human performance.
Symptoms are "geo engineering", such as taking methodsVolcano eruption, shoot countless sulfurized pellets into the air, increasesunlightThe reflection force to block back, butsulfideIt will destroy the ozone layer and warm upProblem solving, and all human beings have died.
National Academy of SciencesYes, let 50000 mirrorsEnter orbitThe reflection of sunlight can offset the effect of carbon dioxide doubling, but each mirror must have 100square kilometreLarge, infeasible.It seems that "geoengineering" is easier said than done, so we should try to solve the problem.
