6) Space Physics Flashcards
Define Rotation of Earth:
The circular movement of the Earth about its own axis is called as the rotation of the Earth.
Define Average orbital speed:
It is defined using the equation: v = 2??r /T where r is the average radius of the orbit and T is the orbital period
Define Solar system
Solar system is a single term that includes eight planets and their moons in orbit round the sun. Also included in the solar system are the smaller bodies such as the comets., asteroids, and the meteoroids.
Define Orbital distance:
Orbital distance is the term that tells us the time taken by one object to revolve around the other.
Define Orbital duration[ Orbital time}:
Orbital duration is the time taken by one object to completely orbit around the other.
Define gravitational field strength:
Gravitational field strength is a term that indicates the amount of gravitational force that is exerted per unit mass at a particular point.It has a symbol “g”
Define Interstellar clouds of gas and dust:
It is a cloud comprising of dust, plasma and gases present in all the galaxies, including our own.
Define accretion disc
These are structures that surround the celestial objects such as the stars and the black holes.These structures are made of gas, plasma and dust
Define Planetary data:
It refers to the data that gives us information on the different planets based on researches and explorations
Define Stars:
Stars are massive , self-luminous celestial objects, made of Hydrogen and Helium
Define Proto stars:
A protostar is a young star. .It is formed as a result of accretion in the nebula.
Define Stable stars:
In every star, there is the gas pressure that exerts an outward force from the centre and at the same time , there is gravity that is pulling the atoms of Hydrogen and Helium inwards. When the outward pushing force balances the gravitational force, we call the star as a stable tar.Example of a stable star is the Sun.
Define Sun:
The Sun is a very bright, luminous, celestial and a stable star, situated in the spiral arm of the Milky Way galaxy and at the centre of the Solar System.
Define Galaxy:
The word galaxy encompasses billions of stars along with their solar systems,gas and dust held by their gravity. There are more than a hundred billion galaxies in the universe.
Define Milky way:
Milky way is a spiral galaxy that includes our solar system. It has billions of stars, including our Sun.
Define Universe:
Universe refers to the space, time and matter and all the laws that govern them.
Define Light-year
One light-year is the distance traveled in (the vacuum of) space by light in one year.
Define Red giants
These are massive , luminous stars with a very low surface temperature and a high volume , with a reddish-orange hue, in their final stage of stellar evolution and that have exhausted their supply of Hydrogen in their core.Examples: Aldebaran (Alpha Tauri) and Mira (Omicron Ceti).
Define Red supergiants:
Red supergiants are aging giant stars with a minimum of 15 solar masses. [solar mass refers to the mass of the sun, when used as a unit of mass. One solar mass is equal to 1.989 x 1030 kg ]
Define Supernova:
Supernova is a powerful and luminous stellar explosion, that happens when a star has reached the end of its life.Example: Kepler’s Supernova
Define Nebula:
Nebula is a Latin word for fog or cloud.It consists of interstellar clouds consisting of Helium, Cosmic Dust, ionised gases, hydrogen as well as molecular clouds. [There are in all 5 different types of Nebulae, namely;emission nebulae, reflection nebulae, dark nebulae, planetary nebulae, and supernova remnants.
Define Black hole:
A black hole is a region in the space, in which the effect of gravity is so strong, that it lets nothing escape out f it, not even light.The region appears to be black and circular.[ There are approximately 100 billion super massive black holes]
Define Redshift:
Redshift is a phenomenon in which the spectrum of an astronomical object gets displaced towards the longer( red) wavelength.
Define Cosmic microwave background radiation (CMBR):
Cosmic microwave background radiation (CMBR) is the leftover of the cosmic radiation after the big bang.
Define Hubble constant Ho:
Hubble constant is the ratio of the speed at which the galaxy is moving away from the Earth to its distance from the Earth
