Universe — Part 2 MCQs with Explanations

Stars emit colors of many different wavelengths, but the wavelength of light where a star's emission is concentrated is related to the star's temperature - the hotter the star, the more blue it is; the cooler the star, the more red it is.

In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes. This occurs because the pair either forms a binary star (i.e. a binary system of stars in mutual orbit, gravitationally bound to each other) or is an optical double, a chance line-of-sight alignment of two stars at different distances from the observer.

The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The remaining bodies range down to the size of a dust particle.

Earth is the fourth smallest of the planets-though in terms of the rocky planets, it's the largest-but it's the most dense.

The correct sequence of the planets in terms of gravity, in the descending order is Neptune, Saturn, Earth, Uranus. Jupiter - 24.79 m/s 2 (81.33 ft/s 2 ) Neptune - 11.15 m/s 2 (36.58 ft/s 2 ) Saturn - 10.44 m/s 2 (34.25 ft/s 2 ) Earth - 9.807 m/s 2 (32.18 ft/s 2 ) Venus - 8.87 m/s 2 (29.1 ft/s 2 ) Uranus - 8.69 m/s 2 (29.4 ft/s 2 ) Mars - 3.711 m/s 2 (12.8 ft/s 2 ) Mercury - 3.7 m/s 2 (12.4 ft/s 2 )

The correct sequence in decreasing order of their brightness is Venus, Sirius and Mars.

Pluto is considered as a dwarf planet. This is called so because it has not cleared its neighbourhood around its orbit. International Astronomic Unit declared it a Dwarf Panet in 2006. It orbits in a disc-like zone beyond the orbit of Neptune called the Kuiper belt, a distant region populated with frozen bodies left over from the solar system's formation.

Earth is the third inner planet and the one we know best. Of the four terrestrial planets, Earth is the largest, and the only one that currently has liquid water, which is necessary for life as we know it.

Kepler through his 'planetary law of motion' proved that every planet has an elongated path. Kepler had believed in the Copernican model of the solar system, which called for circular orbits, but he could not reconcile Brahe's highly precise observations with a circular fit to Mars' orbit – Mars coincidentally having the highest eccentricity of all planets except Mercury.

As compared to the orbit of the other given planets, Mars has nearest orbit to Sun. In the so-called perihelic opposition Mars is closest to the Sun and is particularly close to Earth: Oppositions range from about 0.68 AU when Mars is near aphelion to only about 0.37 AU when Mars is near perihelion.

Jupiter revolves or orbits around the Sun once every 11.86 Earth years, or once every 4,330.6 Earth days.

Venus takes 243 Earth days to rotate on its axis whereas it takes 224.7 Earth days to revolve round the Sun.

We need to figure out which of these planets has the most moons . Option A: Uranus is a large, icy planet, but it doesn't have the most moons. Option B: Jupiter is a giant planet known for its Great Red Spot and has many moons. Option C: Saturn is famous for its beautiful rings, and it also has a large number of moons . Currently, Saturn has the maximum number of satellites . Option D: Neptune is another icy giant planet, but it has fewer moons than Saturn. Therefore, the correct answer is C: Saturn.

The atmosphere of the sun is composed of several layers, mainly the photosphere, the chromosphere and the corona. It's in these outer layers that the sun's energy, which has bubbled up from the sun's interior layers, is detected as sunlight. The lowest layer of the sun's atmosphere is the photosphere.

After 26th General Assembly of International Astronomical Union held in 2006 in Prague (Czech Republic), Pluto was categorised as 'Dwarf Planet'. Its orbit around the Sun larger than the other 3 given planets. Sometimes Neptune is far from sun and sometimes Pluto , before 1999 Neptune was the farthest planet but after 1999 Pluto is the farthest planet for next 238 years .

In a solar or lunar eclipse, the region of earth's shadow is divided into three parts. The three parts are – Umbra, Penumbra and Antumbra.

Ursa Major is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its latin name means "greater she-bear", standing as a reference to and in direct contrast with nearby Ursa Minor, the lesser bear.

In astrophysics, it is a hypothetical concept. In this theory white hole which is opposite to black hole emits stars and energy. In general relativity, a white hole is a hypothetical region of spacetime which cannot be entered from the outside, although matter and light can escape from it. In this sense, it is the reverse of a black hole, which can only be entered from the outside and from which matter and light cannot escape.

In 2126 it will be a bright naked-eye comet reaching about apparent magnitude 0.7.

Mercury is the closest planet to the Sun, orbiting at an average distance of 57.9 million km.

The sky appears blue because the sunlight is scattered by the gas molecules in the atmosphere - a phenomenon known as Rayleigh scattering - named after the discoverer - a British physicist who also discovered Argon - Lord Rayleigh (1842-1919). So, if there was no atmosphere, the sky would appear black.

The planet Mercury is often cited as the most difficult of the five brightest naked-eye planets to see. Because it's the planet closest to the Sun, it never strays too far from the Sun's vicinity in our sky.

The correct sequence of planets in the descending order of their equatorial diameter is Uranus, Earth, Mars, Mercury.

The Foucault pendulum is a simple device named after French physicist Léon Foucault and conceived as an experiment to demonstrate the Earth's rotation.

Our solar system is so big it is almost impossible to imagine its size if you use ordinary units like feet or miles. The distance from Earth to the Sun is 93 million miles (149 million kilometers), but the distance to the farthest planet Neptune is nearly 3 billion miles (4.5 billion kilometers).

Mars is often called the 'Red Planet' because it appears in the sky as an orange-red star. The colour caused the ancient Greeks and Romans to name it after their god of war. Today, thanks to visiting spacecraft, we know that the planet's appearance is due to rust in the Martian rocks.

The statements that are correct with regard to Milky Way are - it is a spiral galaxy and the solar system resides in one of its spiral arms.

Neptune has 14 moons, all named after various sea gods and nymphs in Greek mythology. Almost half of Neptune's moon discoveries occurred decades after NASA's Voyager 2 spacecraft swung past the planet and its system, demonstrating how far telescope technology has progressed. All of Neptune's moons derive their respective names from Greek mythology. They are: Naiad, Thalassa, Despina, Galatea, Larissa, Hippocamp, Proteus, Triton, Nereid, Halimede, Sao, Laomedeia, Psamathe and Neso. This arrangement has been done keeping in mind their closeness to their planet.

It's the time it takes for a distant star to return to the same position in the sky, and it differs from the solar day because the Earth revolves around the Sun as it rotates on its own axis; there is one more sidereal day than solar day each year. A sidereal day is approximately 23 hours, 56 minutes, 4.0916 seconds.

Venus is the closest planet to Earth (it's also the most similar in size). But its proximity to our planet depends on the orbits of both. The two planets travel in ellipses around the sun, and so the distance between them is constantly shifting.

As Earth moves (rotates) from West to East, so stars appear to be more in West than East. So when we say that stars "move", it could be because of the Earth, because of their own movements, or because of both the Earth takes roughly 24 hours to spin on its axis, moving from east to west.

The largest planet in our solar system by far is Jupiter, which beats out all the other planets in both mass and volume. Jupiter's mass is more than 300 times that of Earth, and its diameter, at 140,000 km, is about 11 times Earth's diameter.

Johannes Kepler published his first two laws about planetary motion in 1609, having found them by analyzing the astronomical observations of Tycho Brahe.

According to the size of the planets the descending order will be Jupiter (largest planet), Saturn (2nd largest), Uranus (3rd largest) & Neptune (4th Largest).

Being the largest planet of solar system, its mass is one thousandth of the mass of the Sun. Jupiter, the giant among giants, has enough mass to make 318 Earths. Its diameter is about 11 times that of Earth (and about one tenth that of the Sun).

We can say that one astronomical unit (AU) represents the mean distance between the Earth and our sun. An AU is approximately 93 million miles (150 million km). It's approximately 8 light-minutes. More exactly, one astronomical unit (AU) = 92,955,807 miles (149,597,871 km).

While Copernicus rightly observed that the planets revolve around the Sun, it was Kepler who correctly defined their orbits. At the age of 27, Kepler became the assistant of a wealthy astronomer, Tycho Brahe, who asked him to define the orbit of Mars. Brahe had collected a lifetime of astronomical observations, which, on his death, passed into Kepler’s hands. (Brahe, who had his own Earth-centered model of the Universe, withheld the bulk of his observations from Kepler at least in part because he did not want Kepler to use them to prove Copernican theory correct.) Using these observations, Kepler found that the orbits of the planets followed three laws.

Neptune is the eighth and farthest planet from the Sun, at a distance of about 4.5 billion km (2.8 billion miles) or 30.07 AU.

Our Solar System has eight planets which orbit the sun. In order of distance from the sun they are; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

The largest planet in our solar system by far is Jupiter, which beats out all the other planets in both mass and volume. Jupiter's mass is more than 300 times that of Earth, and its diameter, at 140,000 km, is about 11 times Earth's diameter.