19. Our Galaxy Has a Massive Halo of Gas and Old Stars
If you aren’t already staggered enough by the vastness of space and our galaxy, here’s another titanic measurement: our galaxy is surrounded by a halo of hot gas that extends for hundreds of thousands of light-years. What does this mean? The halo, which comprises gas and the remnants of old stars, is believed to be at least as large as the entire Milky Way Galaxy itself. Also, just like the galaxy, the halo is rotating rapidly. The CHANDRA telescope first found evidence of this halo, which is indicated to extend at least 300,000 light-years beyond our galaxy but may go even further.
And if there is a halo that enormous, what other possibilities are out there? We could say the sky is the limit, but we have already surpassed the atmosphere’s threshold. You will probably hear Beyonce’s song “Halo” in a completely different light now. Are you feeling pretty small in a big world full of billions of stars and opportunities? Just wait until you discover how many stars are floating in the sky — keep reading to see the magical number!
20. We Don’t Know Exactly How Many Stars Are There
Have you ever wondered how many stars are in the sky? On a clear night, you can spot hundreds of thousands of teeny tiny lights twinkling in the distance. However, counting stars is not as easy as it might sound, especially when we know there are at least 200 billion in our galaxy. Pinpointing an exact number is almost impossible by any sort of visual detection method, as many stars are too dim for our current equipment or shrouded behind dust. Even if you could count them all, would you really want to? It would take an astronomical amount of time to count each and every single one — and to keep track of the ones you already counted!
The more common method used is to observe the speed of stars’ orbits within the galaxy, which gives an idea of the gravitational tug and therefore allows a rough estimation of the mass of the galaxy. This mass is then divided by the average mass of a star. However, given the number of times we had to say “rough,” “estimate,” and “average,” it should come as no surprise that there is a fair bit of room for error in this calculation. When it comes to counting stars, would you accept a difference of a billion or so? We may never know the real answer to how many stars are in the sky.