Perihelion, all stars aroundsunlightThe orbit of revolution is roughly an ellipse, its major axis andStub shaftThe difference is small, and it can be approximated to a perfect circle.The sun is at the focus of this ellipse, so when stars move in orbit, they are sometimes close to the sun, sometimes far away, and the closest position to the sun is called perihelion.
At the beginning of January, the Earth was closest to the sun, 147.1 million kilometers, which is called perihelion.
At the beginning of July, the earth was farthest from the sun, 152 million kilometers, which is called aphelion.In fact, when the Earth is at perihelion,Northern HemisphereIn winter,southern hemisphereIt is summer. At aphelion, it is summer in the northern hemisphere and winter in the southern hemisphere.At perihelionEarth revolutionThe speed is fast and slow at aphelion.For the lunar calendar, the position near the perihelion is the most difficult for leap months to appear.
At perihelion, the earth receivessolar radiationStronger (near), the average temperature of the earth's entire atmosphere reaches the highest in January;butLowest temperatureNot at aphelion, but in October (occasionally in September).
Facts show thatNCEPData calculation), the global average wind energy in the whole atmosphere is usually the largest in August and the smallest in April.
In thisCentral force fieldFor a rotating object,angular momentumIt is conservative, including at perihelion and aphelion, specifically L=MV (near) R (near)=MV (far) R (far)
For a specific object, M remains unchanged, and V is perpendicular to its line with the sun.
The point at which a planet is closest to the sun.When the object is the Earth instead ofSolar timeThen use“Perigee”One word（perigee）；periapsisIt is used to orbit other stars.(opposite to aphelion)
Calculation of perihelion correlation formula
Celestial orbits can only have one perihelion, while aphelion can have no or one.
Mercury: perihelion in itsTrack planeMove up, move forward every 100 years (astronomy calledPrecession）About 5601 ", based onNewton's lawThe calculated value is 43 "higher, which is calledMercury perihelion anomalous precession。In 1859,NeptuneFrench astronomer, the discoverer ofLeverrier (Urbain Le Verrier) Inspired by the discovery of Neptune, he boldly proposed this phenomenon because an unknownAquatic planetsCaused by the perturbation of Mercury.In the same year, someone claimed to have discovered the aquatic planets and named them“Vulcan ”, and the search for Vulcan began.However, decades later, this dream has not been fulfilled.So people imagine various factors to explain this complex precession, but there is no satisfactorytheoretical explanation 。
Celebrity computing
After Newton, in 1915, the great scientist Einstein establishedGeneral relativity, cleverly explaining Mercury'sPerihelion precessionPhenomenon: After a planet orbits the sun, its perihelion in orbit will move forward.General relativity has uncovered the mystery of the perihelion precession of Mercury. In turn, the perihelion precession of Mercury has become one of the three most powerful astronomical verifications of general relativity.The other two are,Total solar eclipseWhen the stars are in the sungravitational fieldBending in andWhite dwarfSpectral linered shift。
Perihelion and ecliptic plane
In 1859, astronomerLeverrier findMercuryPerihelion precessionObservations, according toNewton's lawThe calculated theoretical value is faster than 38 per hundred yearsAngular second。In 1882,newcon After recalculation, the excess precession value of Mercury perihelion is 43 angular seconds faster per hundred years.He suggested that it might be caused by MercuryZodiacal lightThe motion of Mercury is damped by the dispersion material of.In 1915, Einstein calculated the residual precession of Mercury's perihelion in "Explaining the Motion of Mercury's Perihelion with General Relativity".
Einstein put forward a formula for the precession of Mercury in 1915, and solved that the precession of Mercury in 100 years is 43 ".Many people use this as one of the most important evidences to support Einstein's theory.
Einstein's formula is: Δω=24 π ^ 3 * α ^ 2/c ^ 2T ^ 2 (1-e ^ 2)
In this regard,Wu DayouSir carefully wrote: "In theMercuryIn the case of observation, many corrections (such as interference from other stars) need to be made first. The total value of these corrections is 5160 ", and the remaining 43" is less than 1% of the total value.Therefore, it seems inappropriate to make a final conclusion on the consistency between theory and observation.However, according to the opinions of experts, it is believed that observation supports Einstein's theory. "In the 1960s, people found thatsunlightWind. It is generally believed that the sun passes throughsolar windAnnual loss 3X10-14M ⊙!
Einstein's 1915 calculation obviously did not include the concept of solar wind!
When discussing the precession of Mercury, the introduction of the concept of solar wind means that the sun's gravity on Mercury will be reduced by at least 3X10-12 times every 100 years.
The second meaning of introducing the concept of solar wind is the extrapolation of solar wind to Mercury!According to the law of conservation of momentum mv=M v '.M isMercuryThe received solar wind action, v is the solar wind speed;M is the mass of Mercury, and v 'is the velocity change of Mercury.
The orbital value of Mercury is about 5.79 million kmOblatenessAbout 0.2056.The radius of Mercury is about 2439km.sphereArea formulaS=4Π .R.R。The spherical area of the orbit of Mercury is about 421227.6x10 ˆ 12Km2.Mercury covers an area of about 4672114.5km2, with a ratio of 9.017x109 ˆ.Solar massIt is about 1.99x10 ˆ 33g, and the mass of Mercury is about 3.303x102 ˆ 3g.considersolar system、GalaxyEqualPlane structureIt can be assumed that the solar wind is mainly lost in the sunEquatorial surface。In addition, considering the oblateness of Mercury's orbit and the gravitational effect of Mercury on the solar wind, the solar wind material obtained by Mercury will be increased by a factor of 100.100 yearsMercuryThe obtained solar wind material is about 3.32X10-20M ⊙.
The maximum speed of the solar wind at the earth is about 900 Km/S.The minimum amount of material on the surface of the sunDisengagement speedAbout 624 Km/S.The solar wind speed at Mercury is about 780 Km/S.
Simply substituting the above values into the formula mv=M v ', we can get that v' is about 7.84X10-5m/S per hundred years.
The gravitational change caused by the solar wind is not negligible compared with the 43 "precession of Mercury per hundred years caused by the sum of extrapolation.
You know MercuryRevolution periodAbout 88earth dayThe motion of Mercury every hundred years 100x4.14x360x60x60 is also compared with the 43 "precession every hundred yearsAstronomical figures。
Of course, when I started to consider the solar wind factor, I thought about doing the "N body" calculation of celestial bodies.But as time goes by, we realize that this is impossible at present.
Will the introduction of solar wind into the "N-body" calculation of Mercury precession support Einstein's theory?
Einstein's calculation of Mercury precession in 1915 can be considered to beNewton equationAdjust the coefficient to fit the known 43 "!Because the "N-body" of Mercury precession will be at least millions of words in length, not just an ordinary paper!
viewpoint
Announce
edit
Perihelion longitude distribution
According to NewtonLaw of universal gravitationThe difference between the calculated perihelion precession of Mercury and the observed value.In 1859, French astronomerLeverrier The observed value of the perihelion precession of Mercury is compared withNewton's lawThe calculated theoretical value is 38 ° faster every century, and it is speculated that this may be a water closer to the sun than MercuryInner planetAttract.However, after years of hard searching, this conjectured planet has never been found.Newcomb measured this value as 43 degrees per century.He suggested that this might be caused by the damping of diffuse matter that emits zodiacal light.However, this hypothesis cannot explain the motion of other planets.So Newcomb doubted the square in the law of universal gravitationinverse ratioThere is a problem with the law.In order to explain the actual motion of several inner planets at the same time, Newcomb found that the gravity should be inversely proportional to the distance to the power of 2+1.574 × 10.At the end of the 19th centuryElectromagnetic theoryIn the early period of development, Weber, Riemann and others also tried to use electromagnetic theory to explainMercuryThe precession of perihelion has not achieved satisfactory results.
The divergence problem caused by the difference between the theoretical value of Mercury perihelion precession calculated according to Newton's law of universal gravitation and the observed value obtained from actual observation.In 1859, French astronomer UJ. J. Leveyer's discovery that the precession value of Mercury's perihelion obtained from many observations is 38 seconds faster than the theoretical value calculated according to Newton's law of universal gravitation every century has attracted the attention of many astronomers. Many people have studied and corrected this problem.The difference between the observed and theoretical precession of Mercury's perihelion is 43 seconds per century, so some people doubt whether Newton's law of gravity is universally applicable.But for a long time, it has not been fully explained.Until 1915, Einstein calculated the precession of Mercury's perihelion according to the general relativity principle he founded. The difference between his calculated value and the value calculated according to Newton's law of universal gravitation was 43 ″ 03 per century.This value is very close to the observed value, which successfully explainsMercuryAbnormal precession of perihelion.
The bifurcation problem of precession values has become one of the most powerful verifications of general relativity in astronomy.There are many factors that affect the precession of Mercury's perihelion, and any small change will affect the verification of general relativity. Therefore, this problem needs further research.
Near point precession
Announce
edit
Due to otherMegaplanets(MainlyJupiter）Perturbation effect of,Earth revolutionPerihelion of orbitPrecessionPhenomenon, the cycle is about 21000 years, about 1.03 'every year, that is to say, every 58 years, the Earth delays one day to reach the perihelion. For example, in 1250 AD, the time when the Earth reached the perihelion was near the winter solstice, while in modern times, it reached the perihelion on January 3 or 4 every year.
In the long run, although the precession of the Earth's perihelion is small, it is also one of the important factors that cause the change of the Earth's climate.YugoslaviaastronomerMilanMilankovich proposed in 1930Geological periodClimate change andthe earth 's axisInclinationChanges in the Earth's orbitEccentricityThe change of is related to the position change of perihelion.
Other comets
Announce
edit
Swift-Tuttle
Perseid meteor showerOfMeteoroidComet Swift Tuttle with a period of 135 yearscometNear the orbit, gravity moves these fromCometary nucleusThe scattered dust and debris attract to the earth and rush into the atmosphere at a high speed. After friction and combustion, they emit a brief light, which is the meteor we see.The larger meteoroidwakeIt can last for several minutes in the night sky.
Comet 109P/Swift Tuttle passed the perihelion in November 1992.The next time comet le will pass through the perihelion again in 2126.
On March 20, 1970,Comet BennettPassing perihelionCometary tailIt has been up to 11 degrees, with brightness of 0, etc.Later foundAt dawnIn the eastern sky before, the comet tail day gradually grows to more than 20 degrees, thick and curved orangeDust comet tailIt is beautiful and easy to distinguish from the blue gas comet tail stretching in a straight line.It has beenHalley's CometOne of the most brilliant comets since the return, many astronomers have taken beautiful pictures.
Comet Bennett was founded on December 28, 1969 bySouth AfricaAmateur astronomerBennettFound and named.
Halley's Comet is the only one that can be predictedBig cometIn 1705, the British astronomer Harley used NewtonLaw of universal gravitationCalculateRegression cycleIn recognition of his achievements, the comet was named Halley.It became an "acquaintance" with 32 regression records since 240 BC.Halley's CometThe cycle of is about 76 years.It appeared twice in the 20th century.In 1910, the conditions for the return were good, so the image was quite spectacular: passing the perihelion on April 20Cometary tailIt was bright enough to be seen by the naked eye, and the tail was 125~150 degrees when it passed the perigee a month later.At that time, because it was only 25 million kilometers away from the earth, some people worried that it was completely covered by the comet tailTerrestrial organismAll will die.In fact, the tail of the comet is very thin, and there is no abnormality on the earth.However, the scene of Halley's Comet sweeping the sky really made people jumpy at that time.
Celestial phenomena
Announce
edit
Perihelion and aphelion solar radiation
At 13:15 on March 5, 2002Henan ProvinceKaifengcityAstronomerZhang Daqing and JapanAmateur astronomerChi Guxun jointly discovered "Chigu Zhang" at the beginning of last monthcomet”Astronomers have calculated its orbit. It will pass through the perihelion on March 18, which will provide a good opportunity for many domestic astronomers to observe a new comet.It is reported that "Comet Chigu Zhang" has gradually approached the perihelion, and the comet will appear in the southwest sky when darkness falls every day for more than ten days,Horizon heightAbout 20 °, small size with a diameter of about 5cm can be usedAstronomical telescopeObservation.Especially from March 15-20, the brightness of this comet will continue to increase, and its brightness is estimated at 4the magnitudeOn the left and right, a dandelion like bright spot can be seen with the naked eye in the suburbs where there is no light interference and the atmosphere is relatively quiet, that is, "Chi Gu Zhang Comet"
In 2021, the Earth'sApohelionIt appears on July 5, and the perihelion is January 2, which is the closest point to the sun in the earth's orbit.[2]
At 8:38 on January 3, 2024, the Earth moved to the perihelion of orbit, which is the closest time for the Earth to the sun in this year. At that time, people will see the "largest sun" in 2024.[3]
