Astronomy and Space Science
Section 1)
The Sun and its family
Ancient astronomers could see the Sun, Moon, and brightest planets with their naked eyes; their
observations and calculations of these bodies' motions gave origin to the science of astronomy. The
amount of knowledge on the motions, characteristics, and make-up of the planets and other smaller
bodies has increased to enormous proportions, and the range of observational tools now includes
galaxies outside of the solar system as far as the edge of the known universe. The solar system,
however, continues to serve as both the outermost point of the physical reach and the foundation of
theoretical understanding of the universe. The information gathered by Earth-launched space
probes and landers about planets, moons, asteroids, and other bodies has been combined with
measurements made by telescopes and other instruments below and above the Earth's atmosphere.
The solar system is made up of the Sun and the objects in its orbit, eight planets (The planets, in
order of their distance outward from the Sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, and Neptune) with more than 210 moons known to exist, numerous asteroids, some of
which have satellites, comets, and other icy bodies, as well as vast stretches of the interplanetary
medium, which is made up of highly flimsy gas and dust.
Mercury
Mercury, the smallest planet in our solar system and the one closest to the Sun, with a distance of
57,909,050 Km according to “university today”, is just a little bit bigger than the Moon. The Sun
would be visible from the surface of Mercury as being up to seven times brighter and more than
three times as huge as it is from Earth. Very hot and frigid temperatures can be found on Mercury's
surface. The planet's proximity to the Sun causes daytime highs to occasionally exceed 800°F
(430°C). Temperatures can drop as low as -290°F (-180°C) at night if there isn't an atmosphere to
,trap that heat. Mercury is close to the Sun, but Venus, which is also close by, has the record for
having the hottest planet in our solar system. Venus, which is likewise near to the Sun, holds the
distinction of being the solar system's hottest planet notwithstanding Mercury's proximity to the
Sun.
Due to its proximity to the sun, which makes any atmosphere the planet could have be blown away
by solar winds and flares, Mercury does not have an atmosphere. However, because mercury is so
tiny, its gravity, which is 3.70 m/s2, is insufficient to hold onto any atmosphere. Mercury's elliptical
orbit has an orbital period of 88 earth days, or how long it takes to circle the sun. They would need
58 days to complete one rotation of the earth, which revolves anticlockwise and revolves three
times for every two orbits.
A solid inner core, a molten outer core, a rocky mantle, and a solid crust make up Mercury.
Mercury's core, which is the planet's exposed core, protrudes from the planet's centre to the surface
by 85%. The chilly lava that makes up Mercury's surface hardens into an enhanced crust. Mercury is
the smallest terrestrial planet, with a radius of 1,516 miles, a surface area of 74.8 million km2, and a
mass of 3.301 X 1023 kg. In opposed to the Jovian planet, which has gas giants, it is thought of as a
terrestrial planet because it is stony and dusty.
According to theory, Mercury used to be close to Mars and 170 million kilometres from the sun,
where life was forming. Mercury also struck an early planet, scattering its crust and mantle, which
eventually coalesced to form Venus.
https://solarsystem.nasa.gov/planets/mercury/in-depth/
Venus
Venus is Earth's nearest planetary neighbour and is located 108,208,930 kilometres away from the
Sun, according to "cool cosmos." It is one of the four inner, rocky terrestrial planets and is frequently
referred to be Earth's twin due to similarities in size and density. There are significant variances
between the two worlds, yet these are not identical twins. Venus is permanently cloaked in thick,
yellowish sulfuric acid clouds that trap heat and contribute to a runaway greenhouse effect. Venus
also has a thick, toxic atmosphere that is packed with carbon dioxide. Despite Mercury being closer
to the Sun, it is the planet with the highest temperature in our solar system. Venus' surface
temperatures are roughly 900 degrees Fahrenheit (475 degrees Celsius) hot enough to melt lead
because of the planet's dense atmosphere, which traps all the heat inside and is made up of 96.5%
carbon dioxide. The atmosphere can crush a car due to its 89 earth atmospheres of pressure. Venus
demonstrates that it is unable to support life as we understand it. The surface is rust-coloured,
covered in thousands of massive volcanoes, strongly crushed mountains, and other geological
features. There may still be some active volcanoes, according to scientists.
, The radius of Venus' iron core is 3,200 kilometres, and it is surrounded by a mantle made of hot rock
that is slowly churning due to the planet's intense heat. Venus' surface may be a thin crust of rock
that bulges and slides as its mantle shifts, forming volcanoes in the process.
Venus has a cloud cover that reflects and scatters sunlight, resulting in a brilliant white surface.
Venus is covered in valleys, mountains, and countless volcanoes. A virulent 880 degrees are reached
at the surface. In Venus, greenhouse emissions and clouds of sulphuric acid droplets make up the
majority of the atmosphere. Venus has a high surface temperature of 470 degrees Celsius, and the
atmosphere includes multiple layers with radically varied temperatures. Venus has a diameter of
12,104 kilometres and a mass of 4.867 x 1024 kg. No moons orbit Venus. Venus doesn't have rings.
Venus rotates in a "backwards rotation," going from east to west. Every 243 days on Earth, that
world completes one spin. Venus completes one complete cycle around the sun in 225 days on
Earth. Venus doesn't experience discernible seasons due to its three degree axial tilt.
https://solarsystem.nasa.gov/planets/venus/overview/
Earth
The only planet we are now aware of that is host to life creatures is our planet, which is located third
from the Sun. Earth is the only planet in our solar system having liquid water on its surface, while
being only the fifth largest planet overall. Earth is the largest of the four planets nearest to the Sun,
all of which are composed of rock and metal, and is only slightly larger than adjacent Venus. It has
been called Earth for at least a thousand years. Except for Earth, every planet has a name derived
from a god or goddess of ancient Greece or Rome. Yet, the word "Earth" originates from German
and simply means "the ground." The inner core, outer core, mantle, and crust are the four primary
layers that make up the earth.
Inner core: a solid sphere with a radius of 1221 km constructed of iron and nickel metals,
with a maximum temperature of 5400 degrees Celsius.
The 2300 km thick outer core is composed of fluids containing iron and nickel.
Mantle: a 2900km thick, heated, viscous slurry of molten rock with the consistency of
caramel.
Crust: Its depth is roughly 30 kilometres. The crust is thinner at the ocean's bottom and
stretches for around 5 km from the ocean's floor to its mantle.
With a radius of 6371 kilometres, Earth is the largest planet in our solar system. Mountains, valleys,
and volcanoes can all be found on Earth. Huge plates that are continually shifting make up the
lithosphere of Earth, which contains both crusts. When plates contact or grind against one another,
mountains are created, which causes earthquakes. The boundaries of the plates are collision,
destructive, conservative, and constructive plates. 78% of the atmosphere on Earth is composed of