Space Part-1

Total Questions: 9

1. Highly dense stars are called: [Uttarakhand Lower Sub. (Pre) 2010]

(a) Supernova
(b) Neutron stars
(c) Binary stars
(d) Asteroid

Correct Answer: (b) Neutron stars

Solution:The highly dense stars are called Neutron stars.

2. In the universe, what are pulsars? [69th B.P.S.C. (Pre) 2023]

(a) A group of stars
(b) Rotating neutron stars
(c) Explosion of a star
(d) Radio waves emitted by a star

Correct Answer: (b) Rotating neutron stars

Solution:Most neutron stars are observed as pulsars. Pulsars are rotating neutron stars observed to have pulses of radiation at very regular intervals that typically range from milliseconds to seconds. Pulsars have very strong magnetic fields which funnel jets of particles out along the two magnetic poles.

3. Consider the following pairs: [I.A.S. (Pre) 2023]

Objects in space — Description

Cepheids — Giant clouds of dust and gas in space
Nebulae — Stars which brighten and dim periodically
Pulsars — Neutron stars that are formed when massive stars run out of fuel and collapse

How many of the above pairs are correctly matched?

(a) Only one
(b) Only two
(c) All three
(d) None

Correct Answer: (a) Only one

Solution:Cepheids, also called Cepheid Variables, are stars which brighten and dim periodically. This behavior allows them to be used as cosmic yardsticks out to distances of a few tens of millions of light-years. Hence, pair 1 is not correctly matched.

4. Electrically charged particles from space travelling at speeds of several hundred km/sec can severely harm living beings if they reach the surface of the Earth. What prevents them from reaching the surface of the Earth? [I.A.S. (Pre) 2012]

(a) The Earth’s magnetic field diverts them towards its poles.
(b) Ozone layer around the Earth reflects them back to outer space.
(c) Moisture in the upper layers of atmosphere prevents them from reaching the surface of the Earth.
(d) None of the statements (a), (b), and (c) given above is correct.

Correct Answer: (a) The Earth’s magnetic field diverts them towards its poles.

Solution:Electrically charged particles from space traveling at speeds of several hundred km/sec cannot reach the surface of the Earth because the Earth's magnetic field diverts them towards its poles. Its best example is "Aurora."

5. If a major solar storm (solar flare) reaches the Earth, which of the following are the possible effects on the Earth? [I.A.S. (Pre) 2022]

GPS and navigation systems could fail.
Tsunamis could occur at equatorial regions.
Power grids could be damaged.
Intense auroras could occur over much of the Earth.
Forest fires could take place over much of the planet.
Orbits of the satellites could be disturbed.
Shortwave radio communication of the aircraft flying over polar regions could be interrupted.

Select the correct answer using the code given below:

(a) 1, 2, 4, and 5 only
(b) 2, 3, 5, 6, and 7 only
(c) 1, 3, 4, 6, and 7 only
(d) 1, 2, 3, 4, 5, 6, and 7

Correct Answer: (c) 1, 3, 4, 6, and 7 only

Solution:Solar flares are brief and powerful eruptions of high-energy radiation from the Sun's surface, associated with sunspots. The phenomenon is known to cause radio and magnetic disturbances on Earth. Massive solar flares can disrupt power grids, interfere with high-frequency airline and military communications, disrupt Global Positioning System signals, interrupt civilian communications, and pose risks to spacecraft and astronauts. Solar flares could interrupt shortwave radio communication of the aircraft flying over polar regions.

Solar flares can temporarily alter the upper atmosphere creating disruptions with signal transmission from, say, a GPS satellite to Earth causing it to be off by many yards. In case of coronal mass ejection or CME, these solar explosions propel bursts of particles and electromagnetic fluctuations into Earth's atmosphere. Those fluctuations could induce electric fuctuations at ground level that could blow out transformers in power grids. CME's particles can also collide with crucial electronics onboard a satellite and disrupt its systems.

During an extreme solar flare event, the auroras(usually which are only visible in the far northern and souther polar regions) could become very intense and could be visible in places that usually never see these elusive night lights. Occurrence of tsunami and forest fires are not associated with the solar flares.

6. The terms 'Event Horizon', 'Singularity', 'String Theory' and 'Standard Model' are sometimes seen in the news in the context of: [I.A.S. (Pre) 2017]

(a) Observation and understanding of the Universe
(b) Study of the solar and the lunar eclipses
(c) Placing satellites in the orbit of the Earth
(c) Placing satellites in the orbit of the Earth

Correct Answer: (a) Observation and understanding of the Universe

Solution:The terms 'Event Horizon', 'Singularity', 'String Theory' and 'Standard Model' are sometimes seen in the news in the context of observation and understanding of the Universe.
In astrophysics, an event horizon is a boundary beyond which events cannot affect an observer. In an expanding universe, the speed of expansion reaches — and even exceeds — the speed of light, preventing signals from traveling to some regions. With reference to black holes, 'event horizon' is the boundary defining the region of space around a black hole from which nothing (not even light) can escape.
Singularities are regions of space where the density of matter, or the curvature of spacetime, becomes infinite. In such locales, the standard concepts of space and time cease to have any meaning. Singularities are predicted to occur in all black holes and also in certain models of the Universe.
String theory is a concept in theoretical physics that states the universe is constructed by tiny vibrating strings, smaller than the smallest subatomic particles. According to this theory, as the strings vibrate, twist and fold, they produce effects in many, tiny dimensions that humans interpret as everything from particle physics to large-scale phenomena like gravity.
The Standard Model of particle physics is the theory describing three of the four known fundamental forces (electromagnetic force, weak nuclear force, and the strong nuclear force — excluding gravity) in the universe and classifying all known elementary particles.

7. Black-hole is: [U.P.P.C.S. (Pre) 2019]

(a) a flight recorder in aeroplane
(b) a spot on the sun
(c) a place in Antarctica
(d) a collapsed star

Correct Answer: (d) a collapsed star

Solution:A black hole is actually a collapsed star. Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses may form. A black hole is a place in space where gravity pulls so much that even light cannot get out. The gravity is so strong because matter has been squeezed into a tiny space.

8. Assertion (A): Black hole is such a celestial existence which cannot be seen by telescope. [U.P.U.D.A./L.D.A. (Pre) 2001]

Reason (R): The gravitational field of black hole is so strong that even light does not escape from it.
Code:

(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

Correct Answer: (a) Both (A) and (R) are true, and (R) is the correct explanation of (A).

Solution:A black hole is an object which is so compact that its gravitational force is strong enough to prevent light or anything else from escaping. For this reason, one can't see it by telescope.

9. Black Hole — [Uttarakhand P.C.S. (Pre) 2007]

(a) Does not emit any radiation.
(b) Converts UV radiation to infrared.
(c) Absorbs all radiations that fall on it.
(d) Is an imaginary concept.

Correct Answer: (c) Absorbs all radiations that fall on it.

Solution:A black hole absorbs all radiations that fall on it due to its high gravity.