Comparable in size to the earth. What makes Earth an ideal place to live? VII

"The first exoplanet orbiting a star similar to our Sun was discovered in 1995. Exoplanets, especially small, Earth-like worlds, only emerged from the realm of science fiction 21 years ago. Today, after thousands of studies, astronomers are ready to announce the discovery what people have dreamed of for thousands of years - another Earth," the announcement says.

The briefing, which will be broadcast on the NASA website, will be attended by NASA management representative John Grunsfeld and three scientists - John Jenkins, Jeff Coughlin and Didier Chielo.

Later at the briefing, scientists reported that they had indeed found a new Earth - an exoplanet comparable in size to Earth, in the "habitable zone" of a solar-like system - Kepler-452b. There should be liquid water on it.

Kepler-452b is 60% larger than Earth in size and five times more massive. It receives 10% more heat from its star than the Earth from the Sun. This does not harm the planet due to its massiveness and fairly open water surface. Considering the evolution of the central star and the orbit of Kepler-452b, it has already spent six billion years in the “habitable zone” of its star and will remain there for another 500 million years. A year on the planet “Kepler-452b” lasts 385 days - only 20 days longer than that of Earth. The distance to this planet from us is 1.4 thousand light years.

The central star belongs to the spectral class "G2" - it is exactly the same star as our Sun in mass and temperature. This star alone is 1.5 billion years older than the Sun (six billion years). This planetary system is located in the constellation Cygnus. The distance from the star to the planet Kepler-452b is 1.05 AU. (157.5 million km.).

Previously, Kepler took a break from observing distant stars and kept an eye on Neptune and its moons for 70 days, allowing scientists to produce a 30-second video of their cosmic “dance.”

Kepler, designed specifically to search for exoplanets, was launched in May 2009. The device constantly monitored the stars in a small area of ​​the sky in the area of ​​the constellation Cygnus and looked for planets, recording weak fluctuations in the brightness of these stars as the planets passed across the disk of the luminary.

In May 2013, the telescope failed, but experts found a way to continue its operation as part of the so-called K2 mission.

Last May, NASA officially approved the telescope's resurrection and extended its funding for two years. In December, Kepler made its first "second life" discovery, discovering the super-Earth exoplanet HIP 116454b in the constellation Pisces.

Before the breakdown, Kepler was aimed at one point in space and monitored only a small corner of the sky, which is located at the junction of the constellations Cygnus and Lyra. After the “resurrection,” the telescope monitors different parts of the sky, since NASA specialists have to constantly rotate it so that sunlight does not enter the telescope lens.

Ecology

All the main publications on the planet have recently talked about the closest star system to us: a planet comparable in size to the Earth revolves around the star Alpha Centauri B. By astronomical standards, this planet is very close to us.

Despite the fact that this planet is similar in size to Earth, it is most likely completely barren, the researchers reported.

Astronomers have discovered an exoplanet near the Sun-like star Alpha Centauri B, which is part of a three-star system located just 4.3 light-years from the Solar System. Called Alpha Centauri Bb, the planet is roughly the same mass as Earth, but its surface is likely covered in hot rock as its orbit is 25 times closer to its star than Earth's orbit is to the Sun.

"We're pretty sure there's no chance for life on this planet."- said the researcher planets Sara Seager. But what allows our planet to support life? Why is our Earth so special?

There are several components necessary for life to exist, according to scientists, but debate continues over what limitations living things might actually have. There are some special species on Earth that exist and thrive in the most seemingly extreme and unsuitable conditions for life.

Here are the components that a planet needs in order for life to arise on it, at least in our usual understanding:

Water

“First, you need some kind of liquid medium in which the molecules can react.”, says Seeger. In such a soup, the ingredients for life as we know it, such as DNA and proteins, can float and interact with each other for the reactions that life requires to take place.

The most common liquid on Earth that is suitable for such a “solution of life” is water. Water is an excellent solvent in which many substances can dissolve. Water has special properties, for example, unlike other liquids, when it turns into a solid state - ice, it can remain on the surface of liquid water, that is, it acts as an excellent insulating substance, preventing the remaining layers from freezing. If ice sank in water, all layers of water bodies would freeze, making chemical reactions for life impossible.

Astronomers searching for extraterrestrial life often look to planets that are in the so-called habitable zone, orbiting their parent stars. In such orbits, planets receive just enough stellar heat to keep water in a liquid state. The Earth is located in just such a habitable zone. Mars and Venus, the planets closest to Earth, no longer fall into this zone. If the Earth were located even a little closer or further in relation to the Sun, life would probably never have arisen on it, it would have been the same lifeless desert as on Mars, or the Earth would have been a foggy oven like Venus.

Of course, alien life doesn't necessarily play by the same rules as Earth's inhabitants.

Astrobiologists are increasingly talking about looking beyond traditional habitable zones. For example, while liquid water does not currently dominate the surface of Mars or Venus, there may once have been a time when this was not the case. At that time, life could well have developed on these planets and either moved to safer places on these planets, for example, went underground, or adapted to a harsher environment, as organisms did extremophiles living on Earth in extreme conditions. Or both.

At the same time, the liquid environment of other planets can also harbor life. For example, Saturn's moon Titan contains liquid methane and ethane.

Energy

The second thing life requires is energy. Without energy, almost nothing will work. The most obvious source of energy for a planet or satellite is its parent star. In the case of Earth, sunlight triggers photosynthesis in plants. Nutrients, in turn, which are created as a result of photosynthesis, are the fuel that almost all living things rely on directly or indirectly.

An infinite number of living organisms on Earth, however, subsist on other sources of energy, such as chemicals from deep-sea sources. There is no shortage of energy sources on Earth.

Time

Scientists say that habitable worlds require stars that live for at least several billion years. This time is enough for life to evolve on them.

Some stars live only a few million years and die. However, life can arise relatively quickly, so age in this case is not so important, scientists say, but age is important when it comes to complex life forms.

For example, the Earth appeared approximately 4.6 billion years ago. The oldest known organism is about 3.5 billion years old, meaning life appeared 1.1 billion years or less after the planet's origin. However, these were very simple organisms. It takes much longer for complex life forms to arise on the planet. The first multicellular organisms appeared on Earth just some 600 million years ago. Due to the fact that our star, the Sun, can be called a long-liver, there was enough time on the planet for man to evolve.

Circulation

Other researchers suggest that tectonic plates are essential for life to emerge in the world. That is, the surface of the planet must be divided into plates that are constantly moving. Plate tectonics is critical to the circulation of molecules necessary for life.

For example, carbon dioxide helps trap heat from the sun to keep the Earth's surface warm. This gas tends to accumulate in rocks over time, meaning the planet will eventually freeze. Plate tectonics allows these rocks to sink down, where they melt, and the molten rock releases carbon dioxide back into the atmosphere through volcanoes.

Additional factors

Other factors that allow life to exist on Earth include slight variations in solar radiation compared to more volatile stars, as well as a magnetic field that helps protect us from any storms of charged particles that come from the Sun. Strong bursts of radiation could kill life in the earliest stages of development, when it was too vulnerable.

Earth remains so far the only known planet on which life exists due to a unique combination of all the most important factors. However, constant exploration of alien worlds may one day change the situation. Maybe someday we will be able to find a planet that has all the similar or completely new attributes that allow life to exist on it.

Goals:

• To develop knowledge about the solar system, its composition, and the place of the Earth in the solar system.
• Develop abstract thinking, the ability to highlight the main thing in a popular science text, and argue your point of view.
• To cultivate aesthetic feelings and interest in research work.

Equipment: photographs of the planets of the Solar System; tables: distances of planets from the Sun, diameters of planets, number of satellites, temperatures on the surface of planets; title plates: Giant Planets, Cosmic Crumbs, Terrestrial Planets; signs with the names of the groups: Experts, Cosmonauts, Researchers, Observers; envelopes with tasks for each group, computer, tape recorder.

DURING THE CLASSES

I. Organizational moment

II. Introduction to the topic

People have been living on Earth for a long time. Once upon a time, none of them knew how to read or write, then parents showed their children the stars and drew constellation patterns in the sand with a stick.
The Starry Sky was the first Great Book that people learned to read and understand. And then, many years later, the science of stars and other luminaries appeared, which is called astronomy translated from Greek means astron – star, nomos- law.
Science developed and many of the secrets of the Universe that it kept were solved. Today we will only touch on some of them.

III. Lesson topic message

Teacher. Lesson topic: Solar system: Earth and others... And who are these others? What place do they occupy in the solar system? We have to find out all this today in class. To do this, we are going with you on a space journey in groups. Each team has its own task. A successful outcome will depend on the work of each of you. You need to prepare for any trip. We do not take unnecessary items with us. We need: a pencil, the ability to work together, be attentive and, of course, knowledge. Let's start with a warm-up. Those who remember and know the answers to questions speak from the spot, and those who have forgotten remember.

IV. Warm-up

• A device for studying the Universe? ( Telescope)
• What is closer to Earth: the Sun or the Moon? (Moon)
• The moon is... (Satellite)
• The path of the planet around the Sun? (Orbit)
• What is the name of the brightest night star? (Sirius)
• Which star can you use to navigate at night? (Polar)
• Hottest stars by color? (White)
• What color is the sun? (Yellow)
• Clothes for astronauts. (Space suit)
• The gaseous shell surrounding the Earth. (Atmosphere)

– Ready for the journey! It's time to introduce you to the tasks

V. Group assignments

Teacher. Commanders will receive assignments and get to work. I wish you success!

1 group. Astronauts

Exercise. Arrange the planets according to their distance from the Sun.

(For children: photographs with the names of the planets, an answer plan, a table of the distances of the planets from the Sun)

Response Plan:

1. How many planets move around the Sun like the Earth? ___________________________

2. In what order?___________________________________________________________

Table 1

2nd group. Researchers

(For children: photographs of all the planets, answer plan, texts describing the planets, title plate - Terrestrial Planets)

Response Plan:

Of the eight planets in the solar system, there are planets that are similar to Earth, while others are very different from it. We explored all planets, compared with the Earth and came to the conclusion that there are planets similar to the ground:

1. List the planets_______________________________________________________________

2. What do these planets have in common?

– Size (large, small)___________
– Hard surface (yes, no)_________
- Atmosphere? (Not really) _____________
– Satellites (yes, no)____________except___________________________

3. What are these planets called? ___________________________

4. Texts describing planets.

Each student in the group must, based on the description of two planets, choose a planet similar to Earth.

1. The planet closest to the Sun is Mercury

2. The fifth planet from the Sun - Jupiter. It is a huge ball of liquid hydrogen, the lightest gas in the world, but there is so much of it that it is the heaviest planet of all. There are a lot of satellites - 63. Jupiter gets a little heat from the sun, and therefore eternal winter reigns there.

3. The second planet from the Sun - Venus. The surface of Venus is rocky. This planet has a dense atmosphere, but it consists of carbon dioxide, which neither humans nor animals can breathe. The heat on Venus is unbearable, about 500. There are no satellites. In the sky, this planet is visible as the brightest bluish star. Very beautiful and attractive.

4. Uranus located behind Saturn. This planet rotates on its side. Therefore, first one side of it, then the other, faces the sun. The size of this planet is much larger than Earth. And it also consists of gases, like its closest neighbors. The distance from the Sun does not allow this planet to heat up. Satellites – 27.

5. Mars- fourth planet. It is half the size of the Earth. A year on Mars lasts twice as long as on Earth. Mars has an atmosphere, but it consists mainly of carbon dioxide. Scientists have been able to establish that the solid surface of Mars is covered with orange-red dust, which allows the planet to be seen as a reddish star. The sun is getting worse. Summers are colder than on Earth, and winters are harsher. There are ice caps at the poles. There are days and nights. Mars has two satellites: Phobos (Fear) and Deimos (Horror)

6. The sixth planet is huge Saturn. It is located far from the Sun, so its temperature is very low. Saturn is also a gas planet. This planet is yellowish in color, it is surrounded by amazing rings consisting of ice blocks and stones, they can be seen through a telescope or strong binoculars. Many satellites - 60.

7. Neptune– the eighth planet from the Sun. It appears dark blue because it also consists of gas, methane gas, which burns in our gas stoves. Through telescopes, astronomers notice wispy white clouds on Neptune. Eternal winter reigns there. Satellites – 13.

8. The planet closest to the Sun is Mercury. It is smaller in size than the Earth and has a hard, rocky surface. On this planet it is very hot during the day and extremely cold at night. Mercury has a weak atmosphere. There are no satellites. Mercury moves very quickly around the Sun, 3 times faster than the Earth.

3rd group. Researchers

(For children: photos of the planets, answer plan, texts describing the planets, title plate - Giant Planets)

Response Plan:

We explored all planets, compared with the Earth and came to the conclusion that there are planets dissimilar to the ground:

1. List the planets _________________________________

2. What do these planets have in common?

– Size (large, small) __________________
– Hard surface (yes, no) _________ They consist of ___________________________
- It’s (warm, cold) there, why? ____________________________
– The planets consist of ______________________________
– Satellites (many, few) __________________
– Life (yes, no)_________________

3. What are these planets called? ______________________

4. The texts describing the planets are the same as those used by the second group of researchers.

Each student in the group must, based on the description of two planets, choose a planet that is different from Earth.

4th group. Observers

(Children have photographs: comet, asteroids, meteorite bodies; texts describing celestial bodies; title plate - Space crumbs)

Lyrics

1. They are small, they arise when tiny cosmic particles or pebbles crash into the earth's atmosphere at high speed, heat up in it and burst into flames at an altitude of about 100 km. Some fall to the Earth, sometimes leaving a mark on the Earth's surface.

2. Many of these cosmic bodies differ in shape from balls; they look like large blocks rushing around the Sun. They were placed in two belts:

1) between Mars and Jupiter;
2) behind the planet Neptune

3. These are not very large objects. But when they are close to the Sun, they can often be seen from Earth with the naked eye. They usually appear as small, dimly glowing specks. Occasionally, bright objects appear with long silvery tails that cut through the sky like a searchlight. A long time ago, people associated the appearance of this object with wars and natural disasters.

5 group. Experts

Exercise. Determine which planets in the solar system are record holders.

(Children have tables: diameters of planets, distances of planets from the Sun, temperatures on the surface of planets, number of satellites. Each student receives a task and completes it.)

1. The most distant planet in the solar system? ________________
2. What is the closest planet to the Sun? ______________________
3. A planet comparable in size to Earth?_________________

table 2

1. The largest planet in the solar system________________
2. Smallest planet?______________________________

Table 3

1. The hottest planet
2. The coldest planet
3.Which planet has the most satellites?

Table 4

1. The slowest planet________________
Think about which planet will take the least time to revolve around the Sun. (Mercury – 88 days)
2. The fastest planet_______________________________________________
Think about which planet will take longer to revolve around the Sun? (Neptune - 165 years)
3. This planet is neither the smallest nor the largest, but does it have something that no other planet in the solar system has? (Earth)

Children write down their answers on the board.

VI. Physical education break

Teacher. All groups have completed the tasks, now let's rest. Please stand up and make two rotations around your axis, as our Earth does. (Children rotate counterclockwise. If someone makes a mistake, the teacher reports that the planet Venus rotates this way)

VII. Group reports

VIII. Conclusion

Teacher. Let's summarize. Everyone completed the tasks. Well done! Today in the lesson you learned which celestial bodies are included in the solar system.

Children's answers. Solar System - the Sun, the Earth along with the planets and their satellites, asteroids, comets, meteoroids.

Teacher. The only planet in the solar system on which there is life is the Earth, and we are its inhabitants! Our Earth is the third planet from the Sun. It created favorable conditions for the life of plants, animals and people. The atmosphere, which envelops the Earth in a bluish haze, contains breathable oxygen and protects the Earth from overheating, cooling and impacts from celestial bodies. In addition, most of the surface of our planet is occupied by bodies of water. And water is necessary for all living organisms.

The third planet from the Sun,
Our Earth is smaller than a star.
But she has enough warmth and light,
Clean air and water.
Isn't life on Earth a miracle?
Butterflies, birds, a bug on a flower...
In the most distant, remote town!

IX. Relaxation

Relaxation to the music of L. Beethovin “Moonlight Sonata” (pictures from “Earthly Expanses”).

XII. Consolidation. Games

Teacher. Let's play.

1. Guess which planet could say this about itself.

1. I am the hottest planet in the Universe. The temperature of my surface can reach up to +500 degrees. Named by a woman's name. In ancient Rome she was the goddess of love. ( Venus)
2. I am the planet closest to the Sun. I got my name from the Roman messenger of the gods, the god of trade. I revolve very quickly around the sun in 88 days. (Mercury)
3. I am very old, so I lie on my side and get very cold. (Uranus)

2. Listen to the poems and find out from the description what planet it is.

Poetry:

(Jupiter) – more than all the planets
But there is no land on the planet.
Only hydrogen everywhere
And bitter cold all year round?

(Saturn)– beautiful planet
Yellow-orange color.
And rings of stones and ice
She is always surrounded.

Planet (Neptune) far from Earth
It is not easy to see it through a telescope.
The eighth planet from the Sun,
An icy winter reigns here forever.

(Mars) – mysterious planet.
It is slightly smaller in size than the Earth.
Because of the blood red color
The planet was named after the god of war.

XI. Reflection

Teacher. Guess the riddle:

Some planets in the sky are bored,
And to make it more fun,
Wandering through the whole universe,
They found friends.
What kind of friends are these? (Satellites)

– What satellite does the Earth have? ( Moon)

– If you liked space travel, show the Moon with its horns up; if not, show the Moon with its horns down. (Children show the Moon card)

- Thank you!

Teacher. Science is developing. People have learned a lot about the vast Universe in which we live, learned to launch artificial Earth satellites and fly into space. They sent space rockets to the Moon and other planets, built observatories equipped with modern technology - all this in order to unravel the secrets of the Universe. But there is still a lot to understand and learn; perhaps you will have to do it.

XII. Homework assignment

– Prepare stories about astronauts and space explorers. The lesson is over. Thank you!

Our Solar System consists of the Sun, the planets orbiting it, and smaller celestial bodies. All of these are mysterious and surprising because they are still not fully understood. Below will be indicated the sizes of the planets of the solar system in ascending order, and a brief description of the planets themselves.

There is a well-known list of planets, in which they are listed in order of their distance from the Sun:

Pluto used to be in last place, but in 2006 it lost its status as a planet, as larger celestial bodies were found further away from it. The listed planets are divided into rocky (inner) and giant planets.

Brief information about rocky planets

The inner (rocky) planets include those bodies that are located inside the asteroid belt separating Mars and Jupiter. They got their name “stone” because they consist of various hard rocks, minerals and metals. They are united by a small number or absence of satellites and rings (like Saturn). On the surface of rocky planets there are volcanoes, depressions and craters formed as a result of the fall of other cosmic bodies.

But if you compare their sizes and arrange them in ascending order, the list will look like this:

Brief information about the giant planets

The giant planets are located beyond the asteroid belt and therefore are also called outer planets. They consist of very light gases - hydrogen and helium. These include:

But if you make a list by the size of the planets in the solar system in ascending order, the order changes:

A little information about the planets

In modern scientific understanding, a planet means a celestial body that revolves around the Sun and has sufficient mass for its own gravity. Thus, there are 8 planets in our system, and, importantly, these bodies are not similar to each other: each has its own unique differences, both in appearance and in the components of the planet themselves.

- This is the planet closest to the Sun and the smallest among the others. It weighs 20 times less than the Earth! But, despite this, it has a fairly high density, which allows us to conclude that there are a lot of metals in its depths. Due to its strong proximity to the Sun, Mercury is subject to sudden temperature changes: at night it is very cold, during the day the temperature rises sharply.

- This is the next planet closest to the Sun, in many ways similar to Earth. It has a more powerful atmosphere than Earth, and is considered a very hot planet (its temperature is above 500 C).

- This is a unique planet due to its hydrosphere, and the presence of life on it led to the appearance of oxygen in its atmosphere. Most of the surface is covered with water, and the rest is occupied by continents. A unique feature is the tectonic plates, which move, albeit very slowly, resulting in changes in the landscape. The Earth has one satellite - the Moon.

– also known as the “Red Planet”. It gets its fiery red color from a large amount of iron oxides. Mars has a very thin atmosphere and much lower atmospheric pressure compared to Earth. Mars has two satellites - Deimos and Phobos.

is a real giant among the planets of the solar system. Its weight is 2.5 times the weight of all the planets combined. The surface of the planet consists of helium and hydrogen and is in many ways similar to the sun. Therefore, it is not surprising that there is no life on this planet - there is no water and a solid surface. But Jupiter has a large number of satellites: 67 are currently known.

– This planet is famous for the presence of rings consisting of ice and dust revolving around the planet. With its atmosphere it resembles that of Jupiter, and in size it is slightly smaller than this giant planet. In terms of the number of satellites, Saturn is also slightly behind - it has 62 known. The largest satellite, Titan, is larger than Mercury.

- the lightest planet among the outer ones. Its atmosphere is the coldest in the entire system (minus 224 degrees), it has a magnetosphere and 27 satellites. Uranium consists of hydrogen and helium, and the presence of ammonia ice and methane has also been noted. Because Uranus has a high axial tilt, it appears as if the planet is rolling rather than rotating.

- despite its smaller size than , it is heavier and exceeds the mass of the Earth. This is the only planet that was found through mathematical calculations, and not through astronomical observations. The strongest winds in the solar system were recorded on this planet. Neptune has 14 moons, one of which, Triton, is the only one that rotates in the opposite direction.

It is very difficult to imagine the entire scale of the solar system within the limits of the studied planets. It seems to people that the Earth is a huge planet, and, in comparison with other celestial bodies, it is so. But if you place giant planets next to it, then the Earth already takes on tiny dimensions. Of course, next to the Sun, all celestial bodies appear small, so representing all the planets in their full scale is a difficult task.

The most famous classification of planets is their distance from the Sun. But a listing that takes into account the sizes of the planets of the Solar System in ascending order would also be correct. The list will be presented as follows:

As you can see, the order has not changed much: the inner planets are on the first lines, and Mercury occupies the first place, and the outer planets occupy the remaining positions. In fact, it doesn’t matter at all in what order the planets are located, this will not make them any less mysterious and beautiful.