Introduction
This piece will be part two of my other blog covering the same and similar topics. This specific blog will cover a lot about the universe, movement, and how time works in space.
The scale of the universe
How big is the universe?
- The Milky Way is one of approximately 200 billion galaxies.
- 1011 stars/galaxy x 1011 galaxies = 1022 stars in the universe.
- The universe has as many stars as grains of (dry) sand on all of Earth’s beaches.
How do our lifetimes compare to the age of the universe?
- Constellations change as time goes on, and stars move in our lifetimes.
- The cosmic calendar is a scale on which we compress the history of the universe into 1 calendar year. An image of a cosmic calendar is below:
How do our lifetimes compare to the cosmic calendar?
- Since we are compressing the 14-billion-year history of the universe into one calendar year, 1 month represents about 1.2 billion real years, 1 day represents about 40 million years, and 1 second represents around 440 years.
- The universe was already ⅔ of the way through its history before our solar system even formed.
- Dinosaurs arose the day after Christmas and died on the 30th.
- All of recorded human history occurs in the last 30 seconds of the year.
- You and I were born about 0.05 seconds before midnight on Dec 31st.
How have we come to be?
- The matter in our bodies came from the Big Bang, which produced hydrogen and helium.
- All other elements were constructed from hydrogen and helium in stars and then recycled into new star systems, including our solar system.
Spaceship Earth
How is Earth moving through space?
- Our first motion is rotation. Most of us are moving in circles around the axis at speeds far faster than commercial jets travel, which is why jets cannot keep up with the Sun when going opposite Earth’s rotation.
- Our second motion is orbit, revolving around the Sun once a year. We orbit at speeds of over 100,000 km/hr (kilometers per hour).
- Our third and fourth motions refer to the movement within the local solar neighborhood and the rotation of the Milky Way Galaxy.
- Earth rotates from West to East, clockwise as viewed from the North Pole. Earth’s axis is also tilted by 23.5 degrees, pointing to the star Polaris.
The Sun’s movement
- Our Sun moves randomly relative to the other stars in the local solar neighborhood, finishing an orbit around the galaxy every 230 million years.
- It moves at a relative speed of more than 70,000 km/h.
- Stars are so far away that we cannot easily see their motion.
Hubble telescope
- Hubble discovered that galaxies are carried along with the expansion of the universe. All galaxies outside our Local Group (close galaxies) are moving away from us. The more distant the galaxy, the faster it is racing away from us.
Conclusion
We live on Earth, within the Solar system, within the Galaxy, within…okay, yeah, we get it. We take up a very small fraction of the universe, and it is constantly expanding, pushing galaxies and stars closer or further away from one another. The universe stemmed from the Big Bang, an event that formed the galaxies within the universe and started the creation of many chemical elements from only two of them. We are constantly moving, orbiting the sun once a year, rotating around once a day, and moving relative to other galaxies, Solar systems, and planets.
I hope that this rant about astronomy wasn’t too complicated and that you were able to explore the cosmos with me without too much confusion.
Thank you to Geetha S. for editing this article!
