Origin and Evolution of the Universe

It can be inferred from information presented in the passage that if the density of the universe were equivalent to three hydrogen atoms per cubic metre, which of the following would be true as a consequence ?

Directions: Read the passage and answer the following question:

            After evidence was obtained in the 1920s that the universe is expanding, it became reasonable to ask: will the universe continue to expand indefinitely, or is there enough mass in it for the mutual attraction of its constituents to bring this expansion to a halt? It can be calculated that the critical density of matter needed to break the expansion and “close” the universe, is equivalent to three hydrogen atoms per cubic metre. But the density of the observable universe-luminous matter in the form of galaxies-comes to only a fraction of this. If the expansion of the universe is to stop, there must be enough invisible matter in the universe to exceed the luminous matter in density by a factor of roughly 70.
            Our contribution to the search for this “missing matter” has been to study the rotational velocity of galaxies at various distances from their centre of rotation. It has been known for some time that outside the bright nucleus of typical spiral galaxy luminosity falls off rapidly with distance from the centre. If luminosity is a true indicator of mass, most of the mass would be concentrated toward the centre. Outside the nucleus the rotational velocity would decrease geometrically with the distance from the centre, in conformity with Kepler’s law. Instead we have found that the rotational velocity in spiral galaxies either remains constant with increasing distance from the centre or increases slightly. This unexpected result indicates that the falloff in luminous mass with distance from the centre is balanced by an increase in nonluminous mass.
            Our findings suggest that as much as 90 percent of the mass of the universe is not radiating at any wavelength with enough intensity to be detected on the Earth. Such dark matter could be in the form of extremely dim stars of low mass of large planets like Jupiter, or of black holes, either small of massive. While it has not yet been determined whether this mass is sufficient to “close” the universe, some physicists consider it significant that estimates are converging on the critical value.

Outer space _______.

Directions: Read the following passage and answer the question on the basis of the content of the passage.

The Universe is open and it is ceaselessly expanding. Space means the whole universe, including the earth, while outer space begins where the earth's atmosphere ends and extends in all directions. The study of space and of outer space is, of course, not the common man's cup of tea, but the interests of mankind are deeply involved when space is put to certain uses, not all of which are peaceful. The use of space for civilian flights within a country and for the worldwide air services has brought mankind and continents closer than they ever were. In a matter of hours, a person can fly from one continent to another; the communications gap has been reduced by what seem to be fantastic means through space.

What is 'a mysterious force' given in the passage?

Directions: The passage is followed by five questions. Read the passage carefully and answer the question that follows. For the question four probable answers bearing options (1), (2), (3) and (4) are given. Only one out of those is correct. You have to choose correct answer.

The Hubble enables us to see farther than any telescope on Earth. It has helped us learn about how solar systems and galaxies form, as well as the existence of dark energy, a mysterious force that causes the universe to expand. Hubble, the powerful telescope, is the size of a school bus. It orbits Earth every 97 minutes, moving five miles per second. Since Hubble is beyond Earth’s atmosphere, it can take clearer pictures of outer space than any telescope on Earth.

What does the ‘dark energy’ do, according to the passage?

Directions: The passage is followed by five questions. Read the passage carefully and answer the question that follows. For the question four probable answers bearing options (1), (2), (3) and (4) are given. Only one out of those is correct. You have to choose correct answer.

The Hubble enables us to see farther than any telescope on Earth. It has helped us learn about how solar systems and galaxies form, as well as the existence of dark energy, a mysterious force that causes the universe to expand. Hubble, the powerful telescope, is the size of a school bus. It orbits Earth every 97 minutes, moving five miles per second. Since Hubble is beyond Earth’s atmosphere, it can take clearer pictures of outer space than any telescope on Earth.