Project name

Saschenko O.

Troyanova A.

Group Study Topic

Why do the planets move around the sun?

Problem question (research question)

Where does the universe end?

Research objectives

1. Determine the main characteristics of the Universe;

2. Explore the relationship of planets and stars in the solar system.

Research results

How was the solar system formed?

Scientists have found that the solar system was formed 4.5682 billion years ago - almost two million years earlier than previously thought, giving astronomers new insights into how our planetary system formed, according to an article published in the journal Nature. .

In particular, the shift in the date of the birth of the solar system by 0.3-1.9 million years back into time means that the protoplanetary cloud of matter from which the planets were formed, revolving around the star that is gaining strength, contained twice as much of the rare iron-60 isotope, than has been thought so far.

The only source of this element in the Universe is supernovae, and therefore scientists now have every reason to assert that the solar system was born as a result of a series of explosions of supernovae in close proximity to each other, and not as a result of condensation from an isolated gas and dust cloud, as was previously thought. recently.

"Through this work, we are able to paint a very coherent and exciting picture of a very dynamic period in the history of the solar system," said David Kring of the NASA Lunar and Planetary Institute in Houston, quoted by Nature News.

The beginning of the existence of the solar system is considered to be the appearance in it of the first solid particles rotating in a gas and dust cloud around a nascent star. The main source of knowledge about such particles are mineral inclusions in a special type of meteorites called chondrites. These meteorites, according to the dominant theory in cosmology, in their own way chemical composition reflect the distribution of elements and substances in the protoplanetary gas and dust disk of the early solar system.

The oldest mineral inclusions in them are enriched in calcium and aluminum, and it is the age of these inclusions, according to the theory, that should reflect the age of the solar system.

The main achievement of the team of authors of the new publication - Audrey Bouvier (Audrey Bouvier) and her mentor Professor Menakshi Wadhwa (Meenakshi Wadhwa) from the University of Arizona is the exact dating of the age of such an inclusion in a chondrite meteorite found in the Sahara desert.

To do this, scientists used two various techniques, based on the isotope ratio of lead, as well as the ratio of aluminum and magnesium isotopes. The authors of the article not only managed to identify the most "ancient" age of this inclusion in comparison with all hitherto known scientific objects- 4.5682 billion years - and for the first time to bring the chronometric scales of these two dating methods into line.

The fact is that dating by lead isotopes, although considered reliable, does not allow obtaining a sufficiently accurate age of a particular geological object. With the help of magnesium and aluminum isotope dating, this age can be determined with much greater accuracy, but until recently this type of dating has always shown the age of objects a million years older than lead isotope dating.

Why do the planets revolve around the sun?

There is an invisible force that makes the planets revolve around the sun. It is called the force of gravity.

The Polish scientist Nicolaus Copernicus was the first to discover that the orbits of the planets form circles around the Sun.

Galileo Galilei agreed with this hypothesis and proved it with the help of observations.

In 1609, Johannes Kepler calculated that the orbits of the planets are not round, but elliptical, with the Sun at one of the foci of the ellipse. He also established the laws by which this rotation takes place. Later they were called "Kepler's Laws".

Then the English physicist Isaac Newton discovered the law of universal gravitation and, on the basis of this law, explained how the solar system keeps its shape constant.

Each particle of the substance of which the planets are composed attracts others. This phenomenon is called gravity.

Thanks to gravity, every planet in the solar system revolves in its orbit around the sun and cannot fly away into outer space.

The orbits are elliptical, so the planets either approach the Sun or move away from it.

conclusions

The planets that revolve around the sun make up the solar system. The sun pulls on the planets, and this attraction holds the planets as if they were tied to a string.

Even in ancient times, pundits began to understand that it is not the Sun that revolves around our planet, but everything happens exactly the opposite. Nicolaus Copernicus put an end to this controversial fact for mankind. The Polish astronomer created his own heliocentric system, in which he convincingly proved that the Earth is not the center of the Universe, and all the planets, in his firm opinion, revolve in orbits around the Sun. The work of the Polish scientist "On the rotation of the celestial spheres" was published in Nuremberg, Germany in 1543.

The ideas about how the planets are located in the sky were the first to express the ancient Greek astronomer Ptolemy in his treatise “The Great Mathematical Construction on Astronomy”. He was the first to suggest that they make their movements in a circle. But Ptolemy mistakenly believed that all the planets, as well as the Moon and the Sun, move around the Earth. Prior to Copernicus's work, his treatise was considered generally accepted in both the Arab and Western worlds.

From Brahe to Kepler

After the death of Copernicus, his work was continued by the Dane Tycho Brahe. The astronomer, who is a very wealthy man, equipped his island with impressive bronze circles, on which he applied the results of observations of celestial bodies. The results obtained by Brahe helped the mathematician Johannes Kepler in his research. It was the German who systematized and deduced his three famous laws about the movement of the planets of the solar system.

From Kepler to Newton

Kepler proved for the first time that all 6 planets known by that time move around the Sun not in a circle, but in ellipses. The Englishman Isaac Newton, having discovered the law of universal gravitation, significantly advanced mankind's ideas about the elliptical orbits of celestial bodies. His explanations that the tides on the Earth occur under the influence of the Moon proved to be convincing for the scientific world.

around the sun

Comparative sizes of the largest satellites of the solar system and the planets of the Earth group.

The period for which the planets make a complete revolution around the Sun is naturally different. Mercury, the closest star to the star, has 88 Earth days. Our Earth goes through a cycle in 365 days and 6 hours. Jupiter, the largest planet in the solar system, completes its rotation in 11.9 Earth years. Well, for Pluto, the planet most distant from the Sun, the revolution is 247.7 years at all.

It should also be taken into account that all the planets in our solar system move, not around the star, but around the so-called center of mass. Each at the same time, rotating around its axis, sway slightly (like a top). In addition, the axis itself can move slightly.

The theory of the world as a geocentric system was repeatedly criticized and questioned in the old days. It is known that Galileo Galilei worked on the proof of this theory. It is to him that the phrase that went down in history belongs: “And yet it spins!”. But still, it was not he who managed to prove this, as many people think, but Nicolaus Copernicus, who in 1543 wrote a treatise on the movement of celestial bodies around the Sun. Surprisingly, despite all this evidence, about the circular motion of the Earth around a huge star, there are still open questions in theory about the reasons that prompt it to this movement.

Reasons for the move

The Middle Ages are over, when people considered our planet to be motionless, and no one disputes its movements. But the reasons why the Earth is heading on a path around the Sun are not known for certain. Three theories have been put forward:

• inert rotation;
• magnetic fields;
• exposure to solar radiation.

There are others, but they do not stand up to scrutiny. It is also interesting that the question: “In which direction does the Earth rotate around a huge celestial body?” Is also not correct enough. The answer to it has been received, but it is accurate only with respect to the generally accepted guideline.

The sun is a huge star around which life is concentrated in our planetary system. All these planets move around the Sun in their orbits. The earth moves in the third orbit. Studying the question: “In which direction does the Earth rotate in its orbit?”, Scientists have made many discoveries. They realized that the orbit itself is not ideal, so our green planet is located from the Sun at different points at different distances from each other. Therefore, an average value was calculated: 149,600,000 km.

The Earth is closest to the Sun on January 3rd and farther away on July 4th. The following concepts are associated with these phenomena: the smallest and largest temporary day in the year, in relation to the night. Studying the same question: “In which direction does the Earth rotate in its solar orbit?”, Scientists made one more conclusion: the process of circular motion occurs both in orbit and around its own invisible rod (axis). Having made the discoveries of these two rotations, scientists asked questions not only about the causes of such phenomena, but also about the shape of the orbit, as well as the speed of rotation.

How did scientists determine in which direction the Earth rotates around the Sun in the planetary system?

The orbital picture of the planet Earth was described by a German astronomer and mathematician In his fundamental work New Astronomy, he calls the orbit elliptical.

All objects on the Earth's surface rotate with it, using conventional descriptions of the planetary picture of the solar system. It can be said that, observing from the north from space, to the question: “In which direction does the Earth rotate around the central luminary?”, The answer will be: “From west to east.”

Comparing with the movements of the hands in the clock - this is against its course. This point of view was accepted with regard to the North Star. The same will be seen by a person who is on the surface of the Earth from the side of the Northern Hemisphere. Having imagined himself on a ball moving around a fixed star, he will see his rotation from right to left. This is equivalent to going against the clock or from west to east.

earth axis

All this also applies to the answer to the question: “In which direction does the Earth rotate around its axis?” - in the opposite direction of the clock. But if you imagine yourself as an observer in the Southern Hemisphere, the picture will look different - on the contrary. But, realizing that in space there are no concepts of west and east, scientists pushed off from the earth's axis and the North Star, to which the axis is directed. This determined the generally accepted answer to the question: "In which direction does the Earth rotate around its axis and around the center of the solar system?". Accordingly, the Sun is shown in the morning from behind the horizon with east direction, but is hidden from our eyes in the west. It is interesting that many people compare the earth's revolutions around its own invisible axial rod with the rotation of a top. But at the same time, the earth's axis is not visible and is somewhat tilted, and not vertical. All this is reflected in the shape of the globe and the elliptical orbit.

Sidereal and solar days

In addition to answering the question: “In which direction does the Earth rotate clockwise or counterclockwise?” Scientists calculated the time of revolution around its invisible axis. It is 24 hours. Interestingly, this is only an approximate number. In fact, a complete revolution is 4 minutes less (23 hours 56 minutes 4.1 seconds). This is the so-called star day. We consider a day on a solar day: 24 hours, since the Earth needs an additional 4 minutes every day in its planetary orbit to return to its place.

Today there is not the slightest doubt that the Earth revolves around the Sun. If not so long ago, on the scale of the history of the Universe, people were sure that the center of our galaxy is the Earth, then today there is no doubt that everything is happening exactly the opposite.

And today we will deal with why the Earth and all other planets move around the Sun.

Why do the planets revolve around the sun

Both the Earth and all the other planets of our solar system move along their trajectory around the Sun. The speed of their movement and the trajectory may be different, but they all keep to our natural star.

Our task is to understand as simply and accessible as possible why the Sun became the center of the universe, attracting all the rest to itself. celestial bodies.

Let's start with the fact that the Sun is the largest object in our galaxy. The mass of our luminary is many times greater than the mass of all other bodies in the aggregate. And in physics, as you know, the force of universal gravitation operates, which no one has canceled, including for the Cosmos. Its law states that bodies with less mass are attracted to bodies with more mass. That is why all planets, satellites and other space objects are attracted to the Sun, the largest of them.

The force of gravity, by the way, the same way works on earth. Consider, for example, what happens to a tennis ball thrown into the air. It falls, being attracted to the surface of our planet.

Understanding the principle of aspiration of planets to the Sun, the obvious question arises: why do they not fall on the surface of a star, but move around it along their own trajectory.

And there is a very reasonable explanation for this as well. The thing is that the Earth and other planets are in constant motion. And, in order not to go into formulas and scientific ranting, let's give another simple example. Again, take a tennis ball and imagine that you were able to throw it forward with a force that is not available to any human being. This ball will fly forward, continuing to fall down, being attracted to the Earth. However, the Earth, as you remember, has the shape of a ball. Thus, the ball will be able to fly around our planet along a certain trajectory indefinitely, being attracted to the surface, but moving so fast that its trajectory will constantly go around the circle. the globe.

A similar situation occurs in the Cosmos, where everything and everyone revolves around the Sun. As for the orbit of each of the objects, the trajectory of their movement depends on the speed and mass. And these indicators are different for all objects, as you understand.

That is why the Earth and other planets move around the Sun, and nothing else.

• Translation

The possibilities are almost endless, but why does everything line up?

Hope is not the belief that everything will end well, but the belief that what is happening has a meaning, regardless of the result.
- Vaclav Havel

I received a lot of great questions this week, and I had a lot to choose from. But, in addition to two recent questions about why all the planets rotate in the same direction and why our solar system is unusual, I chose a question from Nick Ham, who asks:

Why do all planets rotate in approximately the same plane?

When you think about all the possibilities, it really seems unlikely.

Today we have marked the orbits of all the planets with incredible accuracy, and found that they all revolve around the Sun in the same two-dimensional plane with a difference of no more than 7 °.

And if you remove Mercury, the innermost planet with the most inclined plane of rotation, everything else will be very well aligned: the deviation from the average plane of the orbit will be about two degrees.

They are also all fairly well aligned with the Sun's axis of rotation: just as the planets revolve around the Sun, so does the Sun revolve around its own axis. And, as might be expected, the axis of rotation of the Sun is within 7° of deviation from [the axes] of the orbits of the planets.

And yet, this state of affairs looks unlikely, unless some force has squeezed the orbits of the planets into one plane. One would expect the orbits of the planets to orient themselves randomly, since gravity - the force that keeps the planets in constant orbits - works the same way in all three dimensions.

One would expect a sort of crowd instead of a neat and consistent set of almost perfect circles. Interestingly, if you move far enough away from the Sun, beyond the planets with asteroids, beyond the orbits of Halley-type comets and beyond the Kuiper belt, you will find exactly such a picture.

So what caused our planets to be in the same disk? In one plane of orbits around the Sun, instead of a swarm around it?

To understand this, let's fast forward to the time of the formation of the Sun: from a molecular cloud of gas, from the same matter from which all new stars in the Universe are born.

When a molecular cloud grows massive enough and becomes gravitationally bound and cold enough to shrink and collapse under its own weight, like the Trumpet Nebula (above, left), it will form dense enough regions in which new star clusters will form (above, right) .

It can be seen that this nebula - and any other similar to it - will not be a perfect sphere. She has uneven elongated shape. Gravity does not forgive imperfections, and because gravity is an accelerating force that quadruples every time the distance is halved, it takes even small irregularities in its original shape and magnifies them very quickly.

The result is a star-forming nebula with a highly asymmetric shape, and stars form where the gas is densest. If you look inside, at the individual stars present there, they are almost perfect spheres, like our Sun.

But just as the nebula became asymmetrical, so were the individual stars that formed within the nebula emerging from imperfect, overly dense asymmetrical clumps of matter within the nebula.

First of all, they will collapse in one (of three) dimensions, and since matter - you, me, atoms, consisting of nuclei and electrons - comes together and interacts, if you throw it at other matter, you will end up with an elongated disk of matter. Yes, gravity will pull most matter towards the center, where the star will form, but around it you will get what is called a protoplanetary disk. Thanks to the telescope Hubble, we have seen such disks directly!

Here's your first clue why you'll end up with something flattened instead of a sphere with randomly floating planets. Next, we need to turn to the simulation results, since we were not present in the young solar system so long to observe this formation with one's own eyes - it takes about a million years.

And that's what the simulations tell us.

The protoplanetary disk, having flattened in one dimension, will continue to contract as more and more gas is attracted to the center. But for now a large number of material gets sucked in, a good deal of it ends up in a stable orbit somewhere on that disk.

Because of the need to preserve such a physical quantity as the angular momentum, which shows the amount of rotation of the entire system - gas, dust, stars, and so on. Because of how angular momentum works, and how it's roughly evenly distributed between different particles inside, it follows that everything inside the disk should move, roughly speaking, in one direction (clockwise or counterclockwise). Over time, the disk reaches a stable size and thickness, and then small gravitational deviations begin to grow into planets.

Of course, in terms of disk volume, there are small differences between its parts (and gravitational effects between interacting planets), and small differences in initial conditions also play a role. The star forming in the center is not a mathematical point, but a large object with a diameter of about a million kilometers. And when you put it all together, it leads to the distribution of matter not in an ideal plane, but in a form close to it.

In general, we only quite recently discovered the first planetary system that is in the process of planet formation, and their orbits are located in the same plane.

A young star at the top left, in the outskirts of the nebula - HL Tauri, located 450 light years away - is surrounded by a protoplanetary disk. The star itself is only a million years old. Thanks to ALMA, a long baseline array that captures light at fairly long wavelengths (millimetre), which are more than a thousand times longer than visible light, we got this image.

This is clearly a disk, with all matter in one plane, while there are dark gaps in it. These gaps correspond to young planets that have collected nearby matter! We don't know which ones will merge together, which ones will be thrown out, and which ones will come close to the star and be swallowed up by it, but we are witnessing a critical stage in the formation of the young solar system.

So why are all the planets in the same plane? Because they form from an asymmetric cloud of gas that collapses first in the shortest of the directions; matter is flattened and held together; it contracts inwards, but turns out to be rotating around the center. The planets are formed due to irregularities in the matter of the disk, and as a result, all their orbits are in the same plane, differing from each other by a few degrees at most.