- A. 25
- B. 26
- C. 27
- D. 28
(c) 27
- A. Bharani
- B. Karthikai
- C. Rohini
- D. Asvini
(d) Asvini
- A. Han Lippershey
- B. Galilio
- C. Nicolus Coppernicus
- D. Ptolomy
(a) Han Lippershey
- A. elliptical galaxy
- B. irregular galaxy
- C. cluster
- D. spiral galaxy
(d) spiral galaxy
- A. GSAT- 13
- B. GSAT- 14
- C. GSAT-17
- D. Way par GSAT-19
(d) Way par GSAT-19
growing or expanding
Nicolus copernicus
The Big Bang Theory
Ursa Major
Aryabhatta
False. The correct statement is that on a full Moon day, when the Sun is setting in the west, the Moon rises in the east. During a full Moon phase, the Moon is on the opposite side of the Earth from the Sun. Therefore, when the Sun is setting in the western sky, the Moon is simultaneously rising in the eastern sky. This is because the Earth is positioned between the Sun and the Moon during a full Moon, causing them to appear on opposite sides of the sky.
True. The word crescent refers to the phases of the Moon where the Moon is less than half illuminated. During the waxing crescent phase, which occurs just after the new Moon, a small illuminated portion of the Moon becomes visible in the western sky. Similarly, during the waning crescent phase, which occurs just before the new Moon, a small illuminated portion is visible in the eastern sky. The crescent shape is characteristic of these phases when the Moon is less than half illuminated by the Sun.
False. The correct statement is that Galileo did not accept the geocentric model. Galileo supported the heliocentric model, which places the Sun at the center of the solar system with planets orbiting around it. Through his observations with the telescope, Galileo discovered evidence that supported the heliocentric theory, such as the moons of Jupiter and the phases of Venus. His support for the heliocentric model was significant in the scientific revolution and challenged the prevailing geocentric view of his time.
False. The correct statement is that our Milky Way galaxy is identified as a spiral galaxy. The Milky Way has a distinctive spiral structure with a central bulge and spiral arms extending outward. It is not classified as an elliptical galaxy, which has an elliptical or oval shape. The spiral structure of the Milky Way is one of its defining characteristics, and it contains hundreds of billions of stars arranged in these spiral arms.
True. The planet Venus in our solar system does not have a moon or natural satellite. Venus is one of only two planets in our solar system that lacks a moon, the other being Mercury. Most other planets have one or more moons orbiting around them, but Venus orbits the Sun without any natural satellites. This is an interesting characteristic that distinguishes Venus from most other planets in our solar system.
1. Rohini was launched using SLV-3, India's first satellite launch vehicle. 2. GSAT-14 was launched using GSLV-D5, demonstrating India's capability to launch heavy satellites into geostationary orbit. 3. GSAT-19 was launched using GSLV Mark III D1, which is India's most powerful launch vehicle. 4. Chandrayaan-2, India's lunar mission, was launched using GSLV-Mark III, enabling the country to reach the Moon. 5. Mangalyaan, India's Mars Orbiter Mission, was successfully launched using PSLV-XL C25, making India the first country to reach Mars in its first attempt.
Irregular galaxies.
Alpha Centauri.
cresent.
Mercury, Venus.
Mars takes approximately 687 days to complete one full orbit around the Sun. This orbital period is significantly longer than Earth's 365 days because Mars is located farther from the Sun than Earth. The greater distance means Mars must travel a much longer path in its orbit, and it moves more slowly in its orbit due to the weaker gravitational pull from the Sun at that distance. This extended orbital period is an important characteristic that distinguishes Mars from the inner planets of our solar system.
The size of the planet Venus appears smallest when it is in the crescent phase. During the crescent phase, Venus is positioned between the Earth and the Sun, and from Earth's perspective, only a small illuminated portion of Venus is visible. This occurs when Venus is closest to the Sun in its orbit, making it appear as a thin crescent in the sky. In contrast, when Venus is in the gibbous phase, it appears larger because it is farther from Earth, even though a larger portion of its surface is illuminated.
The only evidence of the Big Bang theory is a faint glow in space called the cosmic microwave background radiation. This radiation is the leftover heat from the extremely hot early universe and was discovered in 1964. The cosmic microwave background fills all of space uniformly and provides strong observational support for the Big Bang theory, as it is exactly what scientists predicted would remain if the universe had indeed begun from an extremely hot, dense state and has been expanding and cooling ever since.
Spiral galaxy.
Russia launched the world's first artificial satellite, called Sputnik 1, in 1957. This historic achievement marked the beginning of the space age and demonstrated that humans could successfully place objects into orbit around Earth. The success of Sputnik 1 was a major milestone in space exploration and prompted other countries, particularly the United States, to develop their own space programs and launch vehicles.
The epicyclic model was proposed by early astronomers to explain the complex motions of celestial bodies observed in the sky. In this model, a small circle called an epicycle has its center located on the circumference of a larger circle called a deferent. The planets were thought to move along these epicycles while the deferent itself revolved around a fixed central Earth. This geocentric model was developed to account for phenomena such as the retrograde motion of planets, where planets appear to move backward in the sky at certain times. Although the epicyclic model was eventually replaced by the heliocentric model proposed by Copernicus, it represented an important attempt by ancient astronomers to understand planetary motion using the observational data available to them.
The four different types of galaxies are spiral galaxies, which have a rotating disk with spiral arms extending outward; elliptical galaxies, which have an ellipsoidal or spherical shape and contain mostly older stars; irregular galaxies, which lack a distinct structure and are often shaped by gravitational interactions with other galaxies; and barred spiral galaxies, which are similar to spiral galaxies but have a bar-shaped structure of stars extending across the center from which the spiral arms originate.
PSLV : Polar Satellite Launch Vehicle.
GSLV : Geosynchronous Satellite Launch Vehicle.
As the Venus went around the epicycle, as shown in the diagram Venus would exhibit phases.
Also at times the planet would be nearer, making the apparent size grow bigger and at times far making the apparent size smaller.
If the Venus was going around the Sun, and its orbit is inside that of Earth, Venus would appear always near the Sun in the sky.
It can never be seen in the midnight sky. Two when it is near the Earth, it would be brighter and bigger compared to when it is on the other side of the Sun.
Thirdly only if the Venus is revolving around the Sun, it can exhibit gibbous phase, and the size of the gibbous phase smaller than the crescent phase.
If the Venus was revolving around the Earth, we can never see the gibbous phase of the Venus and it would be seen only if it is orbiting the Sun.
A constellation is a recognizable pattern of stars in the night sky when viewed from the Earth.
International Astronomical Union has classified 88 constellations to cover the entire celestial sphere.
Many of the old constellations have Greek or Latin names and are often named after mythological characters.
Ursa Major (Saptha Rishi Mandalam) is a large constellation and it covers a large part of the sky.
The most striking feature of this constellation is a group of seven bright stars known as big dipper (seven Sages in Indian astronomy).
Ursa Minor in Lattin means ‘the little bear’ it lies in the northern sky.
The Pole star – Polaris (Dhrua) lies within this constellation.
The main group, ‘little dipper’, consists of seven stars and is quite similar to that found in Ursa Major.
Mala's argument would be that the universe is extremely vast, containing billions of stars similar to our Sun, each potentially having their own planetary systems. Given this enormous scale, it is statistically probable that many other planets exist with conditions suitable for life, such as the presence of water, oxygen, and appropriate temperatures. Therefore, Earth is unlikely to be the only planet in the entire universe capable of supporting life. I support Mala's view because the universe is so immensely large that it would be improbable for life to exist only on Earth. While we currently have confirmed evidence of life only on Earth, the discovery of thousands of exoplanets in recent years has shown that planets are common throughout the universe. Some of these exoplanets exist in habitable zones where liquid water could potentially exist. Additionally, the chemical building blocks necessary for life, such as carbon, nitrogen, and oxygen, are found throughout the universe in meteorites and interstellar dust. Given these factors, it is reasonable to conclude that life may exist elsewhere in the universe, even if we have not yet discovered it.