Gravitation and Orbital Mechanics

Fill blank (viii).

Directions: Read the following passage and fill the numbered blanks using correct option.

Asteroids are rocks and debris which are the leftovers of the construction of our solar system. Most are in a belt, which ___(i)___ between Mars and Jupiter. However, the gravitational influence of the giant planets, like Jupiter, or an impact by a comet can knock these large rocks out of their orbit, thus hurling them ___(ii)___ the Earth. Many bodies have struck Earth in the ___(iii)___, and a widely accepted theory blames the impact of an asteroid for the extinction of dinosaurs about 65 million years ago. The scale of such a disaster can be understood by the example of a relatively small-size asteroid strike in Siberia in early 20th century which ___(iv)___ more than half a million acres of forest.
However, what relieves the common, man of the ___(v)___ regarding asteroid impact is the fact that many scientific groups are dedicated towards tracking the asteroid paths and orbit all around the year. With advanced equipments and technology, they can predict any upcoming danger much in ___(vi)___.
According to them the chances of finding such an asteroid crossing Earth in this or the next five generation’s lifetime is only one in thousands. Even if such an asteroid is found out, there will be ___(vii)___ of time to track it, measure its orbit precisely, and plan a system for ___(viii)___ it from its orbit away from that of the Earth’s. There will be no great hurry, and no great panic. It would be a project for all the world’s nations to take part in. It could be a globally unifying event. Because it will be ___(ix)___ long before it actually hits the Earth. It probably would take only a small measure such as chemical rockets, or perhaps an atomic explosion to divert it from a threatening path. Thus, in short, it can be said that though the impact would pose enormous risk to all living forms on Earth, the odds of it occurring within our lifetimes is very ___(x)___ and it is unnecessary to run around believing that the sky is falling.

Which of the following is not true about asteroids?

Directions: Read the following passage and answer the question that follows:

An asteroid is a large rock in outer space. Some, like Ceres, can be very large, while others are as small as a grain of sand. Due to their smaller size, asteroids do not have enough gravity to pull themselves into the shape of a ball. 
Asteroids are left over materials from the formation of the Solar System. These materials were never incorporated into a planet because of their proximity to Jupiter's strong gravity.
The asteroid belt is divided into an inner belt and an outer belt. The inner belt, which is made up of asteroids that are within 250 million miles (402 million km) of the Sun, contains asteroids that are made of metals.
The outer belt, which includes asteroids 250 million miles (402 million km) beyond the Sun, consists of rocky asteroids. These asteroids appear darker than the asteroids of the inner belt, and are rich in carbon.

Inner belt and outer belt differ in

Directions: Read the following passage and answer the question that follows:

An asteroid is a large rock in outer space. Some, like Ceres, can be very large, while others are as small as a grain of sand. Due to their smaller size, asteroids do not have enough gravity to pull themselves into the shape of a ball. 
Asteroids are left over materials from the formation of the Solar System. These materials were never incorporated into a planet because of their proximity to Jupiter's strong gravity.
The asteroid belt is divided into an inner belt and an outer belt. The inner belt, which is made up of asteroids that are within 250 million miles (402 million km) of the Sun, contains asteroids that are made of metals.
The outer belt, which includes asteroids 250 million miles (402 million km) beyond the Sun, consists of rocky asteroids. These asteroids appear darker than the asteroids of the inner belt, and are rich in carbon.

Directions: Read the passage and answer the question.

A comet is an icy small solar system body made up of ices mixed with smaller amounts of dust and rock. It is no larger than few kilometers across. The main structure of a comet is know as nucleus. Comets are composed primarily of many varieties of ice including water, methane and other gases. Comets usually orbit the sun. While planets have a circular orbit, comets' orbits are usually very elliptical. As a comet moves closer to the Sun, the ices begin to fizz. The closest point in its orbit to the Sun is known as “perihelion” and the farthest one is known as “aphelion”. Comets are not any kind of spaceship or alien base. They are bits of solar system material.

_________ is the most distant point to a comet's orbit to the Sun.

Directions: The following question contains paragraph with sentence or phrase missing indicated parenthetically. From the alternatives, select the sentence or phrase that best provides the missing link. As an unseen planet orbits a distant star, the gravitational pull causes the star to move back and forth in space. ( _____ ). The AAT team measures the Doppler shift of stars to an accuracy of 3 metres per second –bicycling speed. This very high precision allows the team to find planets.