From the eyes of the Aliens
Note: This post is much better when read on bigger screens like on a laptop because of the detailed images.
Since childhood we have looked up at the sky and imagined meaningful patterns out of the stars. Not just us, humankind has been doing this since forever. Throughout the history, different cultures have created different figures and outlines on these stars/planets visible in the sky.
The stars visible in the night sky vary throughout the year. As the Earth circles around sun, the part of the sky which Earth faces at night keeps changing. That’s why we see different set of stars in different seasons. Actually if we think about it, Earth takes a full 360˚ rotation in the sky every day. However, sunlight hides everything else in the sky, and thus we only see the stars whenever we are facing away from the Sun.
One may wonder if there is a portion in the sky which is never visible from Earth? The answer is NO. We can cover the full sky by being at multiple locations at different times of the year.
This was simple. Let’s ask a more interesting question here— how will the sky look if we move the observer from Earth to some other location in the space? We have already seen how the sky changes based on the direction Earth is facing at night, but what we can possibly see ever is still constrained by the position of Earth in the Universe. Somehow if we change the position of the observer, the same set of stars which we see on Earth form drastically different patterns in the sky.
Hang on there
Forget about the overwhelming set of stars shown in the first chart, let’s understand this by keeping our observation to a very small portion of it i.e. constellation of Orion. Orion is one of the most prominent constellations and it’s visible throughout the world. We need to know a bit more about it at this moment.
There are seven stars we are looking at(hint: numbers are important):
- Betelgeuse: Red super giant, 642.5 light years away from us
- Bellatrix: Nearest to us in Orion, 244.6 light years
- Rigel: Brightest in Orion, 864.3 light years
- Saiph: Most ordinary star in Orion, 720 light years
- Alnitak: Left most in the belt, 1,262 light years from us
- Alnilam: Most distant star from us in Orion, 2000 lights years
- Mintaka: Right most in the belt, 1200 light years from us
Crazy fact about Mintaka: It’s actually a five star system instead of just one star but we just see it as one star from this far.
Sky of Bellatrix
The stars in Orion have lights years of differences in their depths relative to our location. Let’s look at Orion from one of its member — Bellatrix.
In this picture we are looking at rest of the constellation, looking away from Earth and Solar System. See how the belt is no more a belt when we are looking at it from a different angle and how Alnilam has came out of it to the left. This is crazy. Can you figure out towards which direction should we move our eyes to see Sun in the sky?
Sky of Alnilam
We have seen Orion from the nearest star to us, now let’s see Orion from the farthest star — Alnilam.
We have come so far on the other side of these stars that now rest of the constellation looks much smaller from here. Wait.. where is Bellatrix?
Remember Bellatrix is closest to us and thus farthest to Alnilam? Turns out that Bellatrix is not bright enough to be visible from there. This is a pretty amazing fact. Even though these stars form one of the most distinct constellation in our sky together, they themselves aren’t visible to each other.
In our world, we can see things which are in our line of sight. If we can see someone, that person is also able to see us. However, in the darkness of space, just being in the line of sight is not enough. An object has to be bright enough for its light to reach the other object.
Alnilam is actually a giant blue star with brightness at least 375000 times more than our sun to be visible in our sky.
Coming back to the question of the direction we should look at from Bellatrix to able to see the Sun — turns out that there is no direction you can turn towards, to find Sun in the sky from Bellatrix. Our sun is bright enough only to be visible from ~56.67 light years, which is not enough for it be visible from a ~250 light years away star Bellatrix.
If we want to look at Sun in other system’s sky, we need to find star much nearer to us. Let’s go to Barnard’s star, a very dim star at ~6 light years distance. It’s sky is perfect for us, as our Sun is visible in it alongside Orion in its perfect shape without any distortion.
Do you think in the world of Barnard’s star, Sun is also part of the Orion as the hunter’s tail? Or a stone someone hitting him with from behind?
I can also imagine the Sun as a part of a brand new constellation of Bitcoin from Barnard’s star.
All these images of distant skies are taken from a 3D astronomy program called Celestia. May be there are some other beings out there who can see these unseen skies with naked eyes.
