Tag: mercury

Space Oddities – Part I

By Anupum Pant

Note

During the past few days, I came across a couple of interesting things related to space, which I felt were worth sharing. Individually, none of them could have been made into a good long article. So, I thought of compiling a list of these amusing post-lets to form a single good read.

Also, in the words of Chris Hadfield: Since Space is profound, endless, a textured black, a bottomless eternal bucket of untouchable velvet and untwinkling stars, it is a place that holds infinite possibilities for me to collect more of such amusing ideas. Therefore, I have suffixed the title of this post with a phrase – Part 1 – that leaves an open possibility for other such articles. If you’d like to contribute snippets for the upcoming parts of this post, you can get in touch with me. [About Page]

Space oddities begin

1. A year in Venus:

Two facts. Venus rotates on its axis only once every 243 earth days. It orbits the sun every 224.64 earth days. But, both of these things put together mean that on Venus, a day is longer than a year. Or simply put, almost everyday is everyone’s birthday. Wonderful, isn’t it?
Also, Venus rotates backwards. So, the sun as seen from Venus, rises from the west and sets in the east. The rotation is so slow that it is unable to generate a magnetic field like earth.

2. International Space Station:

Floating around in the ISS, it is often possible for an astronaut to get struck floating in the middle of a room when walls are out of reach. To get out of such a position, astronauts have to be patient and have use the drafts of light crosswinds from fans or call for help for a physical push. – [Source]

3. Going from ‘a planet’ to ‘not a planet’:

Discovered in 1930, Pluto was originally classified as the ninth planet from the Sun. In the year 2006, this definition excluded Pluto and reclassified it as a member of the new “dwarf planet” category.
For the whole time during which Pluto was a planet, it did not complete even half a orbit. That means within half a Pluto year, it went from being called a planet to not a planet. Sad.
Today, Pluto is the tenth-most-massive body observed directly orbiting the Sun or the largest object in the Kuiper belt.

4. Visibility from space:

We have always been told that the only man-made object that can be seen from space is the Great Wall of China, but it is NOT true. You cannot actually see the great wall of China from space.
What you can actually see is the biggest structure made by living organisms (not humans) – The Great Barrier Reef.

5. Sun as seen from Mercury:

On Mercury, the sun appears to briefly reverse its usual east to west motion once every Mercurian year. The effect is visible from any place on Mercury, but there are certain places on its surface, where an observer would be able to see the Sun rise about halfway, reverse and set, and then rise again, all within the same day. [Sun’s unusual behaviour as seen from Mercury]

6. Flying on Titan is easy:

The largest moon of Saturn is a very peculiar place. It is the only known moon to have an atmosphere. But that isn’t all.
Its atmosphere has 1.19 times more mass than the earth’s atmosphere. Secondly, the gravity is far lower as compared to earth. This means, had there been humans on Titan, they would have been able fly in Titan by just flapping wings attached to their arms.

In the end, I’d like to leave you with two very interesting things. An inspirational comic by Zen Pencils and a revised version of David Bowie’s Space Oddity, recorded by Commander Chris Hadfield on board the International Space Station (I had this on repeat the entire time I was writing this article):

The Sun’s Unusual Behavior – Seen from Mercury

by Anupum Pant

The sun – as seen from Earth

For most of us living on Earth (closer to the equator), the sun has followed a simple path throughout the years. It rises, goes up at noon and then sets for rest of the day. It is a simple straight line for the complete year.
For people living a little away from the equator, things get a bit interesting. There, the summer sun at noon is overhead, but the winter sun is low at noon, not overhead. It isn’t very easy for a person living near the equator to grasp this phenomenon well. You’ll have to go there and see for yourself. Or simply, the simulator at the end of this paragraph will help you understand it better.
At poles, the sun almost moves horizontally for many days. It keeps on making a horizontal circle around you. There, it is day for 6 months and night for the next 6 months. [Here is a sun path simulator for Earth]

However, nowhere on earth, things get as interesting as they get in the skies of Mercury.

The sun – as seen from Mercury

On Mercury, the sun appears to briefly reverse its usual east to west motion once every Mercurian year. The effect is visible from any place on Mercury, but there are certain places on its surface, where an observer would be able to see the Sun rise about halfway, reverse and set, and then rise again, all within the same day. It is indeed an unusual performance which isn’t easy for us Earthlings to digest. [See animation in the next paragraph]

Why does it happen?

Let us consider a simpler analogy – some planets (like Mars), as seen from earth, take a similar path. [see the animation for Mars’s path as seen from earth]

The planets, including Earth, all travel around the Sun in a continuous orbit. We can see them make their way across the sky in a straight line usually. However, every now and then a planet appears to turn around. After turning around, it appears to move back the way it came. This is called a retrograde orbit and is caused due to the difference in speeds at which the planets circle the Sun.

So, as we see Mars do a reverse from earth, a similar motion of sun is observed from the surface of Mercury.

[Apparent Retrograde Motion – Wikipedia]