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Nov 26, 20215 min read

Wisley’s Astronomy Briefing Chapter 1: Our Place In The Universe

Updated: Dec 20, 2021

Written by Wisley Lau

Edited by Nishant Kidangan



(Credit: Pinterest)


Suppose you want to send a postcard of RCHK to a distant friend, who lives far far away-not another country but the other side of the universe, how will you write your address? Have no fear, because we are here to teach you how to write your cosmic address using the Universe Map.


Step One: Earth



(Credit: NASA)


After filling in your local address, it is time to first enter planet Earth. The third planet from the sun is the only place in the universe humans know so far to harbor life. With a thin atmosphere with 21% oxygen and a magnetic field powered by the planet’s core, it is strong enough to protect the living things on it from being harmed by ultraviolet light, meteoroids, and radiation. This earth is also a wet planet, with water covering up roughly 71 percent of Earth's surface, most of which is in the oceans, which is the habitat for roughly 2.2 million species, with only 228,450 species are known to humans. Earth is home to an intelligent species called Homo Sapiens, their achievements include landing their own brethren on the surface of Earth’s moon, and creating the internet, that delivers all known information to their fingertips. However, the damage they have done to their planet through global warming and climate change is something many living organisms on the planet are reckoning and trying to stop.


Step Two: The Solar System



(Credit: NASA)


Moving further from Earth, you can see the planetary system that we call the solar system. The Sun, a main-sequence yellow dwarf star at the center, has eight planets revolving around it; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto, which was once named a planet, was demoted in 2006 to a dwarf planet after it failed to meet the criteria that planets should clear the neighborhood around its orbit. The solar system isn’t just made up of a star and planets, it contains hundreds of moons surrounding six out of the eight planets, and the asteroids lying in the asteroid belt between Jupiter and Mars. In the Kuiper belt outside of Neptune, you can visit different dwarf planets including Pluto and other space rocks like Arrokoth. Venturing out to the Oort Cloud, you can see future comets these icy objects that move into the solar system due to the Sun’s gravity and form tails. Truly a beautiful sight for those able to view it.


Step Three and Four: Local Stars and The Milky Way

(Credit: Roen Kelly/Astronomy)


(Credit: Universe Today)


Leaving the solar system, you find yourself among the local stars. Most of these stars are red or yellow dwarfs, meaning they can last a longer period of time. But occasionally there are blue giants like Sirius A living in the local group. Some stars come in pairs or trios, like Sirius A and B, or Alpha Centauri with Alpha Centauri A, B, and Proxima Centauri. The last of which is 4.2 light-years away, the closest to the solar systemThe star has scientists and astronomers speculating that a planet revolving around it might be a potential spot for alien life. Further outwards, you can see the Milky Way galaxy, home to 100 billion stars and with arms spanning up to 100,000 light years across, is the galaxy we live in. You can find the local stars in Orion’s arm. And in the center of the galaxy, there rests a massive black hole called Sagittarius A.Everything in the galaxy spins around the center, with the Sun spinning around 220 kilometers per second!


Step Five, Six, and Seven: Local Group, The Virgo Supercluster, and The Laniakea Supercluster


(Credit: Sky At Night Magazine)


(Credit: Wikimedia Commons)






Entering the Local Group, you can see our galaxy is not alone. Home to 20 galaxies, most of them are elliptical. The two main galaxies, the Milky Way and Andromeda, are predicted to collide with each other after billions of years (see more here). While moving further you can see the Local Group is just a tiny speck in the Virgo Supercluster, a collection of galaxies spanning over 110 million light-years across, which is simply a pinprick compared to the Laniakea Supercluster, a 500 million light-year structure that is discovered in 2014. It is the largest supercluster found to date. These structures are home to thousands, possibly millions of galaxies, which are each fundamental units to an even bigger structure, the Universe itself.


Step Eight: The Observable Universe

(Credit: NASA)



(Credit: Wikipedia)

​

You’ve reached the end. The limits of our observations to the universe. As we go further than superclusters, we discover they are grouped into thread-like structures called filaments. They gather together to form structures like spider webs, forming into the universe at its largest scale. Astronomers hypothesize the shape of the universe to be round, due to observations of galaxies being further away due to the process of redshift. The furthest humans can observe is the CMB or Cosmic Background Radiation, where we have detected the universe in its infancy and a piece of evidence to prove the Big Bang Theory correct.


This is a summary of what we humans have learned about our place in the universe. The author hopes you can gain a sense of perspective to how miniscule we are to the universe. We will be discussing many of the topics and objects featured in this briefing in further detail in the future, but before then, keep on curiosing!


Bibliography:

National Geographic. The Universe Map [Image]. Retrieved from https://i.pinimg.com/originals/3b/3a/20/3b3a205ad2ef43f2f3927c64db5458de.jpg

NASA. (2021). Earth Photo [Image]. Retrieved from https://svs.gsfc.nasa.gov/vis/a010000/a011600/a011650/cy-1024.jpg

Planet Earth: Facts About Its Orbit, Atmosphere & Size. (2021). Retrieved 9 November 2021, from https://www.space.com/54-earth-history-composition-and-atmosphere.html

There are 228,450 known species in the ocean — and as many as 2 million more that remain a total mystery. (2015). Retrieved 9 November 2021, from https://www.businessinsider.com/r-oceans-yield-1500-new-creatures-many-others-lurk-unknown-2015-3

The solar system: Facts about our cosmic neighborhood. (2020). Retrieved 9 November 2021, from https://www.livescience.com/our-solar-system.html

Meet the stars next door. (2019). Retrieved 9 November 2021, from https://astronomy.com/magazine/2019/10/meet--the-stars-next-door

Astronomy. (2019). Nearby Stars [Image]. Retrieved from http://astronomy.com/~/media/6A2A334AA52E4E18ADD684E4F4E46461.jpg

Anglada-Escudé, G., Amado, P., Barnes, J., Berdiñas, Z., Butler, R., & Coleman, G. et al. (2016). A terrestrial planet candidate in a temperate orbit around Proxima Centauri. Nature, 536(7617), 437-440. doi: 10.1038/nature19106

Proxima Centauri - Wikipedia. (2021). Retrieved 9 November 2021, from https://en.wikipedia.org/wiki/Proxima_Centauri

In which direction does the Sun move through the Milky Way?. (2021). Retrieved 9 November 2021, from https://astronomy.com/magazine/ask-astro/2020/07/in-which-direction-does-the-sun-move-through-the-milky-way

Britannica, T. Editors of Encyclopaedia (2019, March 11). Local Group. Encyclopedia Britannica. https://www.britannica.com/place/Local-Group

Milky Way Destined for Head-On Collision. (2012). Retrieved 9 November 2021, from https://www.nasa.gov/mission_pages/hubble/science/milky-way-collide.html

Virgo Supercluster - Universe Today. (2009). Retrieved 9 November 2021, from https://www.universetoday.com/30645/virgo-supercluster/

Gifford, C., & Mitton, J. (2019). Super Space (pp. 10-11). DK.

Shape of the universe - Wikipedia. (2007). Retrieved 9 November 2021, from https://en.wikipedia.org/wiki/Shape_of_the_universe

Cosmic Microwave Background. [Image]. Retrieved from https://upload.wikimedia.org/wikipedia/commons/0/0b/Planck_satellite_cmb.jpg













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