Origin of the Universe, Celestial Phenomena and Observational Tools

The universe, believed to have originated about 13.8 billion years ago with the Big Bang, has been expanding and evolving ever since. This event led to the formation of fundamental particles, atoms, stars, and galaxies. Key concepts such as dark energy and dark matter play crucial roles in our understanding of the cosmos. From defining planets and dwarf planets to exploring various celestial phenomena, the study of space continues to reveal the mysteries of our vast universe.

Comprehensive Overview of the Universe: From Origins to Observational Tools

Origin of the Universe: It is believed that the universe was born about 13.8 billion years ago in an event called the Big Bang. 

• It is the most prevailing cosmological model for the birth of the universe.
• Big Bang Theory: It states that at some moment, all of space was contained in a single point of very high-density and high-temperature state from which the universe has been expanding in all directions ever since.
• • Formation of Subatomic Particles and Atoms: After the initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles and, later, simple atoms.
  • Primordial Elements from the Big Bang: The majority of atoms produced by the Big Bang were hydrogen and helium along with trace amounts of lithium and beryllium.
  • Coalescence of Primordial Element Clouds: Giant clouds of these primordial elements (hydrogen and helium) later coalesced through gravity to form stars and galaxies.
• Dark Energy: It is an unknown form of energy which is hypothesized to permeate (spread throughout) all of space, tending to accelerate the expansion of the universe.
• Dark Matter: It is a hypothetical form of matter that is thought to account for approximately 85% of the matter in the universe. 
  • Dark energy plus dark matter constitutes 95% of the total content of the universe.
  • It is believed that dark matter is considered as the factor for unexplained motion of stars in galaxies.

PLANET

Definition: The most recent definition of a planet was adopted by the International Astronomical Union in 2006. It says a planet must do three things:

• It must orbit a star (in our cosmic neighborhood, the Sun).
• It must be big enough to have enough gravity to force it into a spherical shape.
• It must be big enough that its gravity cleared away any other objects of a similar size near its orbit around the Sun.
• Dwarf Planet: As per the International Astronomical Union (IAU):
  • A dwarf planet is a celestial body that circles the sun, has enough mass to assume a roughly round shape, has not cleared the neighborhood surrounding its orbit, and is not a moon.
  • Examples: Ceres, Pluto, Eris, Makemake, and Haumea are the first five dwarf planets discovered.

Key Terms

Kuiper Belt: The Kuiper Belt is a ring of icy rocks & dust bodies just outside of Neptune’s orbit, known as Kuiper belt objects or trans-neptunians.

• Pluto is the largest known Kuiper Belt Object instead of the 9th planet of our Solar system. 
• There are bits of rock and ice, comets, and dwarf planets.
• Asteroid Belt:  Asteroids are remnants of planetary formation mainly composed of refractory rocky and metallic minerals and some ice, that circle the sun in a zone lying between Mars and Jupiter.
  • The circular chain of asteroids is called the asteroid belt or main asteroid belt.
• Ploonets: A celestial object, which are orphaned moons that have escaped the bonds of their planetary parents.
  • The researchers explain that the angular momentum between the planet and its moon results in the moon escaping the gravitational pull of its parent planet.
• Goldilocks Zone:  The ‘Goldilocks Zone,’ or habitable zone – ‘the region around the star where a planet could sustain liquid water on its surface’.[UPSC 2014]
  • Example: Our Earth is in the Sun’s Goldilocks zone.
  • If Earth were where the dwarf planet Pluto is, all its water would freeze; on the other hand, if Earth were where Mercury is, all its water would boil off.
    • Kessler Syndrome: The Kessler syndrome is a theory proposed by NASA scientist Donald J. Kessler in 1978, used to describe a self- sustaining cascading collision of space debris in LEO.
• Asteroids: Big chunks of rocks float through space and orbit the sun, mostly found in the main asteroid belt i.e.,between Mars and Jupiter.
  • The biggest one is Ceres (940 km wide), twice as big as the Grand Canyon.
• Meteor:  When a meteoroid enters the earth’s atmosphere, it begins to burn up and falls to the ground.
  • This burning trail is known as meteor or falling stars.
• Meteoroid: Smaller rock pieces that break off from an asteroid, and float through interplanetary space.
  • Can be as small as grain of sand or as large as a meter across.
  • Meteorite: If a meteoroid rock doesn’t completely burn up as it falls to Earth– the rock left behind is called a meteorite.

• Comets: Comets are frozen leftovers from the formation of the solar system composed of dust, rock and ices, ranging from few miles to tens of miles wide.

• • • Orbits closer to the sun, they heat up and spew gases and dust into a glowing head visible in the atmosphere.
    • Comets have highly elliptical orbits, unlike planets which have near-circular orbits.

• Van Allen Radiation Belts: It is a zone of energetic charged particles, most of which originate from the solar wind.

• • The particles are captured by and held around a planet by that planet’s magnetic field.
  • These are intense over the Equator and are absent over the poles.

Observing Space through Telescopes

• • Space: It is a three dimensional region that begins where the earth’s atmosphere ends.
  • Telescope: It is an optical tool that observes distant objects using lenses, curved mirrors, or a combination of the two.

• Hubble Telescope

• • • Since its launch, the observatory has produced important discoveries in the area of astronomy. It is the first big optical telescope to be mounted in space.
    • It takes photographs of deep space and aids scientists with their understanding of the cosmos by seeing the furthest stars, galaxies, and planets.

• James Webb Telescope

• • NASA’s primary infrared observatory is the James Webb Space Telescope (JWST).
  • NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA) are working together on this project.
    • It will Look for the first galaxies or bright objects that appeared after the Big Bang.
    • Determine the evolution of galaxies and Observe the evolution of stars from their earliest beginnings through the development of planetary systems.
    • Measure the physical and chemical features of planetary systems, including our own Solar System, and look into the possibility of life elsewhere.

Event Horizon Telescope (EHT) project

EHT is a group of 8 radio telescopes used to detect radio waves from space.

• In 2019, Scientists from the EHT project released the first- ever optical image (or shadow image) of a Black hole located in the center of galaxy Messier 87 in the constellation Virgo.
• Sagittarius A* is the 2nd black hole to get photographed.

Conclusion

Understanding the universe’s origins and the celestial phenomena within it helps us grasp our place in the cosmos. From the Big Bang to the roles of dark matter and energy, these concepts form the foundation of modern astronomy. 

• Telescopes like Hubble and James Webb expand our knowledge, while projects like the Event Horizon Telescope provide unprecedented insights into black holes. 
• This exploration underscores the importance of continuous observation and study of the universe.

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