Extraterrestrial skies: Mars
What would you be able to see if you were standing on the surface of Mars and look at the sky?
First of all, Mars has a very thin atmosphere, but being extremely dusty, there is much light that is scattered about. In many cases the astronomical phenomena from the surface of Mars are similar to those seen from Earth, but sometimes they can also be different. For example, because the atmosphere of Mars does not contain an ozone layer, it is also possible to make UV observations from the surface of Mars.
For a stargazer on the surface of Mars, Earth can easily be seen with the naked eye, as the evening and the morning star - just as Venus is as seen from our world. Both the Earth and the moon would appear starlike, and you could also see Earth’s moon orbiting around Earth once each month. From Earth, we can’t see any other planets’ satellites with the unaided eye, but this amazing sight on Mars would be visible to the eye alone. Since Earth is an inner planet, observers on Mars can occasionally view transits of Earth across the Sun. The next one will take place in 2084.
Aside from having Earth visible in the night sky, Venus would appear as a bright star close to the Sun. Jupiter and Saturn are also visible the night sky, and it should be possible to see Jupiter’s four major moons. The average distance from Mars to Uranus is 2.8 billion km which is about the same as the average distance from Earth to Saturn, so you would be able to see Uranus from Mars - if you know where to look.
Mars’ north pole points to a spot in the sky that’s about midway between Deneb, the brightest star in the constellation Cygnus the Swan, and Alderamin, the brightest star in the constellation Cepheus the King. Meanwhile, in the southern sky as seen from Mars, Kappa Velorum – a fairly bright star in the constellation Vela – is near the martian south celestial pole at about three degrees away.
The Sun as seen from Mars appears to be 5/8 the size as seen from Earth (0.35°), and sends 40% of the light, approximately the brightness of a slightly cloudy afternoon on Earth. The color of the Martian sky during the day is a scarlet or bright orangeish-red color, which comes from the presence of iron-rich dust particles. Around sunset and sunrise, the sky is rose in color, but in the vicinity of the setting Sun it is blue. This is the opposite of the situation on Earth. Twilight lasts a long time after the Sun has set and before it rises, because of all the dust in Mars’s atmosphere. At times, the Martian sky takes on a violet color, due to scattering of light by very small water ice particles in clouds.
Sources: wikipedia | earthsky.org | physics.stackexchange.com | www.universetoday.com |