Astronomy | Astrophysics Answers

One of the many exciting phenomena of special relativity is time dilation. Imagine astronauts

in a spaceship that is passing by the Earth with a high velocity.

(a) Are clocks ticking slower for the people on Earth or for the astronauts on the spaceship?

(b) How fast must the spaceship travel such that the clocks go twice as slow?

The object NGC 4440 is a galaxy located in the Virgo Cluster at the following equatorial coordi￾nates (J2000): 12h 27m 53.6s

(right ascension), 12◦

170 3600 (declination). The Calar Alto Observatory

is located in Spain at the geographical coordinates 37.23◦N and 2.55◦W.

(a) Is the NGC 4440 galaxy observable from the Calar Alto Observatory?

Astronomers need to identify the position of objects in the sky with very high precision. For that, it is essential to have coordinate systems that specify the position of an object at a given time. One of them is the equatorial coordinate system that is widely used in astronomy.

(a) Explain how the equatorial coordinate system works.

(b) What is the meaning of J2000 that oen occurs together with equatorial coordinates?

The object NGC 4440 is a galaxy located in the Virgo Cluster at the following equatorial coordinates (J2000): 12h 27m 53.6s (right ascension), 12◦ 170 3600 (declination). The Calar Alto Observatory is located in Spain at the geographical coordinates 37.23◦N and 2.55◦W.

(c) Is the NGC 4440 galaxy observable from the Calar Alto Observatory?

Scientists are developing a new space cannon to shoot objects from the surface of the Earth directly into a low orbit around the Earth. For testing purposes, a projectile is fired with an initial velocity of 2.8 km/s vertically into the sky. Calculate the height that the projectile reaches, ... (a) assuming a constant gravitational deceleration of 9.81 m/s^2 . (b) considering the change of the gravitational force with height. Note: Neglect the air resistance for this problem. Use 6.67×10^−11 m^3kg^−1 s^ −2 for the gravitational constant, 6371 km for the Earth’s radius, and 5.97 × 10^24 kg for the Earth’s mass.

A total solar eclipse occurs when the Moon moves between the Earth and the Sun and completely blocks out the Sun. This phenomenon is very spectacular and attracts people from all cultures. However, total solar eclipses can also take place on other planets of the Solar System. Determine for each of the following moons if they can create a total solar eclipse on their planet.

Moon Radius Distance to Planet Planet Distance to the Sun

Phobos 11 km 9376 km Mars 228 × 10^6 km

Callisto 2410 km 1.883 × 10^6 km Jupiter 779 × 10^6 km

Titan 2574 km 1.222 × 10^6 km Saturn 1433 × 10^6 km

Oberon 761 km 0.584 × 10^6 km Uranus 2875 × 10^6 km

Note: The radius of the Sun is 696 × 10^3 km.

Telescopes are an essential tool for astronomers to study the universe. You plan to build your own telescope that can resolve the Great Red Spot on the surface of Jupiter at a wavelength of 600 nm. The farthest distance between the Earth and Jupiter is 968 × 106 km and the Great Red Spot has currently a diameter of 16,500 km. (a) Use the Rayleigh criterion to determine the diameter of the lens’ aperture of your telescope that is needed to resolve the Great Red Spot on Jupiter. Impacts have formed many craters on the Moon’s surface. You would like to study some of the craters with your new telescope. The distance between Moon and Earth is 384,400 km. (b) What is the smallest possible size of the craters that your telescope can resolve?

Astronomers need to identify the position of objects in the sky with very high precision. For that, it is essential to have coordinate systems that specify the position of an object at a given time. One of them is the equatorial coordinate system that is widely used in astronomy. (a) Explain how the equatorial coordinate system works. (b) What is the meaning of J2000 that oen occurs together with equatorial coordinates? The object NGC 4440 is a galaxy located in the Virgo Cluster at the following equatorial coordinates (J2000): 12h 27m 53.6s (right ascension), 12◦ 170 3600 (declination). The Calar Alto Observatory is located in Spain at the geographical coordinates 37.23◦N and 2.55◦W. (c) Is the NGC 4440 galaxy observable from the Calar Alto Observatory?

The object NGC 4440 is a galaxy located in the Virgo Cluster at the following equatorial coordinates (J2000):

12h 27m 53.6s (right ascension), 12◦170 3600 (declination). The Calar Alto Observatory

is located in Spain at the geographical coordinates 37.23◦N and 2.55◦W.

Is the NGC 4440 galaxy observable from the Calar Alto Observatory?

Scientists are developing a new space cannon to shoot objects from the surface of the Earth directly into a low orbit around the Earth. For testing purposes, a projectile is fired with an initial velocity of 2.8 km/s vertically into the sky. Calculate the height that the projectile reaches, ...(a) assuming a constant gravitational deceleration of 9.81 m/s2.(b) considering the change of the gravitational force with height.Note: Neglect the air resistance for this problem. Use 6.67×10−11m3kg−1s−2for the gravitational constant, 6371 km for the Earth’s radius, and 5.97×1024kg for the Earth’s mass.

Astronomers need to identify the position of objects in the sky with very high precision. For that, it is essential to have coordinate systems that specify the position of an object at a given time. One of them is the equatorial coordinate system that is widely used in astronomy. (a) Explain how the equatorial coordinate system works. (b) What is the meaning of J2000 that often occurs together with equatorial coordinates? The object NGC 4440 is a galaxy located in the Virgo Cluster at the following equatorial coordinates (J2000): 12h 27m 53.6s (right ascension), 12° 17' 36'' (declination). The Calar Alto Observatory is located in Spain at the geographical coordinates 37.23°N and 2.55°W. (c) Is the NGC 4440 galaxy observable from the Calar Alto Observatory?