Sakurajima – Japan, Kyushu
- Location: Japan, Kyushu island
- Peak: 1117 m a. s. l.
Sakurajima – The volcano is located on the Japanese island of Kyushu. It is not without reason that it is considered one of the most dangerous volcanoes on Earth. Since 1955, it has exploded almost continuously. It age is estimated at 22,000 years. Sakurajima is very close to the city of Kagoshima, inhabited by 700,000 citizens.
The historical testimonies of explosions known to us date back to the 8th century. The largest eruption took place in 1914. Until then, the volcano has not shown any activity for more than a century, so it has already been declared extinct. Due to the strong earthquake, the inhabitants of the island luckily evacuated before the eruption. The lava leak lasted for over a month. As a result of this big explosion, the island began to grow, until it finally merged with the continent.
In 2016, the volcano exploded again. A fire was coming out of it, and a cloud of smoke and volcanic dust was rising above it. Broken pieces of rock fell two kilometers further. The main concern was caused by the relatively close location of Sendai nuclear power plant.
Our planet composition – What is inside the Earth?
Our planet composition – Crust, mantle and core. In this abbreviated way one could characterize three layers of Earth, which were created at the beginning of its existence.
- Lithosphere – Top layer of Earth, which is in direct interaction with other terrestrial spheres, such as the hydrosphere, atmosphere and biosphere.
- Crust – It consists of the oceanic and earth’s crust. The thickness of the earth’s reaches up to 70 kilometers. The oceanic is thinner and its thickness varies between five and ten kilometers.
- Conrad’s discontinuity – Horizontal surface of the discontinuity in the earth’s crust that forms the transition between the upper and lower layers. Its depth varies in different types of crust from 5 to 30 km.
- Mohorovićic’s discontinuity – A layer that geologically defines the passage of the earth’s crust and upper mantle. Occurs in 20-90 kilometers deep under continents, and 10-20 kilometers under the oceans.
- Earth’s mantle – Layer consisting of upper and lower mantle. The upper reaches the depth of 90 kilometers. The lower one is assigned a depth of 650 km to the Earth’s core, and therefore approximately 2,900 km.
- Repetti’s discontinuity – The area between the upper and the lower mantle.
- Gutenberg’s discontinuity – Part of the Earth’s envelope, which is assigned at depth of 2,900 kilometers. Below it is the core of the Earth.
- Core – Geosphere, located in the center of the Earth. It starts at depth of 2,900 kilometers below the surface and covers approximately 31% of the Earth’s mass, with iron and nickel being the largest part of it. The core is twice as heavy as the Earth’s mantle and consists of a semi-internal inner core, which, among other things, creates the Earth’s magnetic field.
KEPLER-442b – Stony exoplanet in superearth class
KEPLER-442b – Stony exoplanet in superearth class, which the parent star is the orange dwarf.
Size: 1,3 Earth
Mass: 2,3 Earth
Equivalent temperature: -65°C
The planet KEPLER-442b, from which light has been running for 1115 years, belongs to the so-called Super-Earth. In this way, rocky exoplanets are determined whose mass does not exceed tenfolds Earth. The parent star of this planet is an orange dwarf. The star larger than a red dwarf, but smaller than a yellow dwarf, which is the Sun. This type of star has calmer youth, and therefore does not send its planetary children too much UV. In addition, the planet is in the ecosphere, so it can not be ruled out that the ocean is splashing on its rocky surface. If it has a more complex atmosphere, it does not have to be at the same time a kingdom of cold. According to some calculations, it is the smaller superearth that are most suitable for life, even more than our own planet.
GJ 273b – Exoplanet in the constellation Little Dog
GJ 273b – Planet orbiting the Luyten star
Size: 1,47 Earth
Mass: 3 Earth
Equivalent temperature: -6°C
Twelve light-years from our solar system, Luyten’s star, the red dwarf, wanders from Earth in the constellation Little Dog. Astronomers have discovered two exoplanets next to it. At the same time one of them belongs to the superearth category and at the same time circulates at the edge of the ecosystem. In contrast to the many other planets whose parent star is a red dwarf, GJ273b knows what day is and what is the night. Usually, the planets move close enough that their rotation is connected, and their parent star only puts one hemisphere.
Ross-128b – 11 light years away from Earth
Ross-128b – The planetary system around the red dwarf Ross 128 for about 70,000 years will become our closest star neighbor.
Size: 1,2 Earth
Mass: 1,3 Earth
Equivalent temperature: 7°C
Even closer than the GJ 273b is the Ross-128b exoplanet. It is away from us, just like a star. Which is a very quiet red dwarf, less than 11 light-years away and gradually approaching us. Based on the obtained data, astronomers have discovered that planet Ross 128b circulates around its star twenty times closer than Earth circulates the Sun. Despite such a short distance, the planet gets only 1.38 times more energy than our planet. Thanks to the cool and stable star, whose surface temperature in comparison with the sun is halved, the equivalent temperature on its surface is estimated to be from -60°C to 20°C.
TRAPPIST-1d – Representative of TRAPPIST-1 sys
TRAPPIST-1d – One of representatives of the TRAPPIST-1 planetary system
Size: 0,8 Earth
Mass: 0,3 Earth
Equivalent temperature: 15°C
The relatively small weight of this planet indicates that its surface can be flooded by a deep ocean.
According to some speculations, here is 250 times more water than in the Earth’s oceans.
The first measurements showed that the planet is moving outside of the living zone, but now it seems that it will enter it safely. Exoplanet can boast a dense atmosphere and is so close to its star that it circulates in four days. It only drops by 4.3% more light than on Earth. Although TRAPPIST-1d circulates its star in synchronous rotation, a dense atmosphere in which there should be a lot of water vapor helps in thermal exchange. The difference between the illuminated and the dark hemisphere is not like that of other celestial bodies.
TRAPPIST-1e – Exoplanet from system TRAPPIST-1
TRAPPIST-1e – The stony exoplanet of the TRAPPIST-1 system, according to physical properties, is the “e” from the planetary system TRAPPIST is the most similar to Earth.
Size: 0,9 Earth
Mass: 0,8 Earth
Equivalent temperature: -22°C
It moves in the middle of the ecosystem of the entire collection, but there is the least water here. TRAPPIST-1e has a smaller size than Earth, but it has a larger mass. Possible inhabitants would have to be smaller in height and more important to cope with the pressure of local gravity. Red dwarfs, to which the TRAPPIST-1 star belongs, do not emit as much light and heat as the Sun. This means that the ecosphere, in which liquid water can sustain in proper conditions, is located in much closer orbits than in our solar system. A year on the planet TRAPPIST-1e lasts six ordinary earth days.
The planet probably also has a compact atmosphere where hydrogen is lacking. This type of atmosphere can also be found on the rocky planets of our solar system. Hydrogen is also a greenhouse gas, if it was a large amount in the local atmosphere, the surface of the planet would be uninhabitable.
TRAPPIST-1f – Rocky exoplanet the size of Earth
TRAPPIST-1f – Rocky exoplanet, from the planetary system around red dwarf TRAPPIST-1
Size: 1,1 Earth
Mass: 0,9 Earth
Equivalent temperature: -65°C
Around the star, 40 light-years away from us, are seven stony planets. The sixth in turn has very similar sizes to Earth. But its density is generally lower. The composition is close to the ice or water worlds of the moon Jupiter – Europe or the moon of Saturn – Enceladus. The first measurements determined that not a small part of the mass of the planet is ice, and that under the surface perhaps liquid water. The atmosphere here is not the densest, so the equivalent temperature probably does not differ from the proper one.