Our current atmosphere has just thermal origins only.
The only atmospheric function is to block solar radiation.
Greenhouse effect has no influence on the life on our planet.
Troposphere plays the great role in weather and climate formation.
There is no water cycle on the Earth.
All the layers of upper atmosphere are similar and there is an ozone layer in each of them.
The Earth is a habitable planet.
Biosphere consists of humans only.
V. What new information have you learned from this article? Have you got anything to add? Discuss it into groups.
VI. Think why are all the Earth’s spheres so important to each other? And what will happen if one of them disappears? Share your ideas.
Magnetic field and the Moon
I. Learn active vocabulary:
Dipole - диполь
convection motion – конвекционное движение
conducting material – проводниковый материал, проводник
electric currents – электрический ток
alignment – магнитный заряд
to deflect – отклоняться, менять направление
Collision - столкновение
energetic charged particles – энергетически заряженные частицы
Torus - полукруглый
aurora – северное сияние
Dwarf - карлик
Attraction - притяжение
solar terminator – солнечная заглушка
lunar phases – фазы луны
torque – крутящий момент
the plane of the ecliptic – плоскость эклиптики
controversial – спорный
Eclipse - затмение
volatile – летучий, переменный
II. Read and translate the text:
Magnetic field
The Earth’s magnetic field, which approximates a dipole.
The Earth’s magnetic field is shaped roughly as a magnetic dipole, with the poles currently located proximate to the planet’s geographic poles. According to dynamo theory, the field is generated within the molten outer core region where heat creates convection motions of conducting materials, generating electric currents. These in turn produce the Earth’s magnetic field. The convection movements in the core are chaotic in nature, and periodically change alignment. This results in field reversals at irregular intervals averaging a few times every million years. The most recent reversal occurred approximately 700,000 years ago.
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The field forms the magnetosphere, which deflects particles in the solar wind. The sunward edge of the bow shock is located at about 13 times the radius of the Earth. The collision between the magnetic field and the solar wind forms the Van Allen radiation belts, a pair of concentric, torus-shaped regions of energetic charged particles. When the plasma enters the Earth’s atmosphere at the magnetic poles, it forms the aurora.
Moon
| Name | Diameter | Mass | Semi-major axis | Orbital period |
| Moon | 3,474.8 km | 7.349×1022 kg | 384,400 km | 27 days, 7 hours, 43.7 minutes |
| 2,159.2 mi | 8.1×1019 (short) tons | 238,700 mi |
The Moon is a relatively large, terrestrial, planet-like satellite, with a diameter about one-quarter of the Earth’s. It is the largest moon in the solar system relative to the size of its planet. (Charon is larger relative to the dwarf planet Pluto.) The natural satellites orbiting other planets are called “moons” after Earth’s Moon.
The gravitational attraction between the Earth and Moon causes tides on Earth. The same effect on the Moon has led to its tidal locking: its rotation period is the same as the time it takes to orbit the Earth. As a result, it always presents the same face to the planet. As the Moon orbits Earth, different parts of its face are illuminated by the Sun, leading to the lunar phases: The dark part of the face is separated from the light part by the solar terminator.
The Moon may have dramatically affected the development of life by moderating the planet’s climate. Paleontological evidence and computer simulations show that Earth’s axial tilt is stabilized by tidal interactions with the Moon. Some theorists believe that without this stabilization against the torques applied by the Sun and planets to the Earth’s equatorial bulge, the rotational axis might be chaotically unstable, as it appears to be for Mars. If Earth’s axis of rotation were to approach the plane of the ecliptic, extremely severe weather could result from the resulting extreme seasonal differences. One pole would be pointed directly toward the Sun during summer and directly away during winter. Planetary scientists who have studied the effect claim that this might kill all large animal and higher plant life. However, this is a controversial subject, and further studies of Mars—which has a similar rotation period and axial tilt as Earth, but not its large Moon or liquid core—may settle the matter.
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Viewed from Earth, the Moon is just far enough away to have very nearly the same apparent-sized disk as the Sun. The angular size (or solid angle) of these two bodies match because, although the Sun’s diameter is about 400 times as large as the Moon’s, it is also 400 times more distant. This allows total and annular eclipses to occur on Earth.
A scale representation of the relative sizes of, and distance between, Earth and Moon.
The most widely accepted theory of the Moon’s origin, the giant impact theory, states that it formed from the collision of a Mars-size protoplanet called Theia with the early Earth. This hypothesis explains (among other things) the Moon’s relative lack of iron and volatile elements, and the fact that its composition is nearly identical to that of the Earth’s crust.
III. Answer the questions:
1. What is the Earth’s magnetic field?
2. How can you explain the generation of magnetic field?
3. What is the role of the magnetosphere?
4. Is aurora physical or optical effect?
5. What is an energetic charged particle?
6. Is the Moon a planet?
7. Is there only one Moon in the Solar system?
8. Where can we see the interaction between the Earth and the Moon?
9. What is tidal locking of the Moon?
10. How does the Moon help to form our climate?
11. How can you explain total and annular eclipses which we can see on the Earth?
12. Do you know any other theories of the Moon formation?
IV. Think over and share your ideas:
If the Moon is a part of our planet and its composition is nearly identical to that of the Earth’s crust, why is there no atmosphere and no life on it?
V. Try to read and understand the following text:
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Give your opinion about the future of our planet.
Future
The future of the planet is closely tied to that of the Sun. As a result of the steady accumulation of helium ash at the Sun’s core, the star’s total luminosity will slowly increase. The luminosity of the Sun will increase by 10 percent over the next 1.1 Gyr (1.1 billion years), and by 40% over the next 3.5 Gyr. Climate models indicate that the rise in radiation reaching the Earth is likely to have dire consequences, including the possible loss of the planet’s oceans.
The Earth’s increasing surface temperature will accelerate the inorganic CO2 cycle, reducing its concentration to the lethal levels for plants (10 ppm for C4 photosynthesis) in 900 million years. The lack of vegetation will result in the loss of oxygen in the atmosphere, so animal life will become extinct within several million more years. But even if the Sun were eternal and stable, the continued internal cooling of the Earth would have resulted in a loss of much of its atmosphere and oceans (due to lower volcanism). After another billion years the surface water will have completely disappeared and the mean global temperature will reach 70°C. The Earth is expected to be effectively habitable for another 500 million years or so.
The Sun, as part of its evolution, will expand to a red giant in about 5 Gyr. Models predict that the Sun will expand out to about 250 times its present size, roughly 1 AU (150,000,000 km). Earth’s fate is less clear. As a red giant, the Sun will lose roughly 30% of its mass, so, without tidal effects, the Earth will be in an orbit 1.7 AU (250,000,000 km) from the Sun when the star reaches it maximum radius. Therefore, the planet is expected to escape envelopment by the expanded Sun’s sparse outer atmosphere, though most, if not all, existing life will be destroyed because of the Sun’s increased luminosity. However, a more recent simulation indicates that Earth’s orbit will decay due to tidal effects and drag, causing it to enter the red giant Sun’s atmosphere and be destroyed.
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