October 18

Comet Tsuchinshan-ATLAS

Written by Zhi Ning, Y1, Communication Studies with a Second Major in Governance and International Relations

This week, we will witness the “comet of the century” as it reaches its closest distance to Earth. Yet I remain struck by a humbling irony: here we are, inhabitants of a lonely blue speck, mesmerised by a beauty that could wipe our existence if it crashed through our atmosphere.

I ponder the chaos behind all that we regard as beauty. How did we come to be? And at what point do we cross the fragile line that separates beauty from tragedy?

Comet C/2023 A3 Tsuchinshan-ATLAS taken from Rabka-Zdrój on October 14th, 2024

To set some context, Comet Tsuchinshan-ATLAS (C/2023 A3) was named after the two observatories that discovered it last year, the Purple Mountain (Tsuchinshan) Observatory in China and an Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in South Africa. It is one of many long-period comets with orbits spanning tens of thousands of years. The last time it was visible from Earth, our species was still migrating out of Africa. However, from the 11th to the 22nd of October this year, it will grace our skies again after 80,000 years.

The Oort Cloud, from which the comet originated, is a hazy shell enveloping our solar system. It is filled with trillions of icy space debris the size of mountains. From that distance, our sun looks like just about any other star, only a little brighter. Delving into the origin of comets really put things into scale for me. Everything as we know it – our home, our world, the folly of our own self-importance – is but a puzzle piece in an infinite expanse of cosmic obscurity, where far more things remain unknown.

Comets trace back to the birth of our solar system billions of years ago. Likewise, our existence is not solely defined by our time on this earth, but by the very beginning of time itself.

In my Writing & Reasoning (SP0001) core module, the concept of big philosophy was introduced to me. Looking at the world through the lens of big philosophy asks us to consider how things intertwine in their broadest possible definitions. It has been argued that our sense of time on Earth has the intrinsic property of an arrow. To be precise, the cosmological arrow of time points away from the origins of the universe and in the direction of its accelerating expansion.

Everything started with the Big Bang 13.8 billion years ago when our universe burst into existence from a singular speck. 4.54 billion years ago, our little blue planet formed, following an intricate web of other chance happenings. It was not until around 200,000 years ago that the first modern humans emerged. Today, our species remains a smudge in the vast traces of metaphysical history, a purely incidental outcome born from a cascading trail of cause and effect.

And what does that make of us?

This October, we will again marvel at the same comet our distant ancestors once did. No matter how much mankind has changed, the reminder that big philosophy offers remains true. To imagine a time before time existed, to imagine a possibility of our paradise lost, reminds us that our world is not as it is by miracle or design. Rather, our time here is as much fleeting as it is a privileged coincidence.

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October 14

Tsuchinshan-ATLAS & Big Philosophy

Written by Dr Melvin Chen, NTU-USP Faculty Member

The comet of the century is getting brighter as it makes its closest pass by Earth this week: C/2023 A3. The two facilities that detected C/2023 A3, Tsuchinshan (紫金山) Observatory and the ATLAS (Asteroid Terrestrial-impact Last Alert System) system, yield its longer, double-barrelled name: Tsuchinshan-ATLAS. Tsuchinshan-ATLAS may be spotted this weekend in Singapore’s skies, without the aid of binoculars or telescopes.

Comet C/2023 A3, or Tsuchinshan-ATLAS, was pictured about 99.4 million miles away from Earth by NASA astronaut Matthew Dominick using long-duration photography on a camera programmed for high sensitivity aboard the International Space Station.

Carl Sagan once remarked that if you wish to make an apple pie from scratch, you must first invent the universe. In a similar vein, if you wish to gaze at the Tsuchinshan-ATLAS comet this weekend, it may be helpful to understand its cosmic context. The Oort Cloud, a cloud representing the gravitational edge of our solar system and far beyond the orbit of Neptune, is thought to contain billions, or even trillions, of icy bodies such as comets. Like all comets, Tsuchinshan-ATLAS consists of frozen remnants from the birth and early formation of our solar system 4.6 billion years ago. Astronomers sometimes refer to comets as dirty snowballs or icy dirtballs. Unlike comets, asteroids are typically rocky or metallic bodies that hail from the asteroid belt within the inner solar system, between the orbits of Mars and Jupiter. Meteorites are fragments of comets or asteroids after they have landed on the surface of a planet.

taken in Australia, CC BY-SA 2.0

As stargazers look forward to the double bill of C/2023 A3 (Tsuchinshan-ATLAS) this weekend and C/2024 S1 (ATLAS) toward the end of this month, it is tempting to wax philosophical about humanity’s enduring interest in small solar system bodies. According to the panspermia hypothesis, life may have originated elsewhere in the universe and emerged on Earth as a result of microbes or seeds brought by asteroids, comets, or meteorites. The Black Stone (al-Ḥajar al-Aswad) of Mecca, a Muslim relic dating back, according to tradition, to the time of Adam and Eve, has been described as a meteorite. When it famously appeared in 1066 (the year of the Norman conquest), Halley’s comet, which passes by Earth roughly once every 80 years, was interpreted as a bad omen for King Harold II of England. King Harold II was eventually defeated and killed by William the Conqueror at the Battle of Hastings. The Bayeux tapestry, an embroidered cloth depicting the events leading up to the Norman conquest, features Halley’s comet at the centre of one of its scenes. Last but not least, according to the Alvarez hypothesis, the impact of a large asteroid on Earth resulted in the Cretaceous-Tertiary (K-T) mass extinction event 65 million years ago. This asteroid impact is believed to have created the Chicxulub crater in the Yucatán Peninsula in Mexico.

C/2023 A3 (Tsuchinshan-ATLAS) on 10 June 2024 as seen from an 8-inch reflector f/4 telescope. 59 30 seconds frames were stacked with DSS and edited in SIRIL.

Whether we regard them as bringers of life, loci of splendour and mystery, auguries and portents, fit subjects for great art, or harbingers and bringers of doom, there is no denying their allure. In ‘Auguries of innocence’, William Blake speaks of seeing a world in a grain of sand. I would like to extend a philosophical challenge to stargazers this weekend: the challenge of seeing the universe and our place in it in a 4.6 billion-year-old dirty snowball.

The writer of this blog post is incidentally an NTU-USP faculty member who is currently pivoting toward big philosophy in terms of his research interests. Big philosophy aims to understand how things in the broadest possible sense of the term hang together in the broadest possible sense of the term, from the Big Bang to the present. Tsuchinshan-ATLAS provides the perfect big-philosophical context for meditating on the nature of the universe and our place in it. A big philosophy component has been incorporated into the NTU-USP core course SP0001 (‘Writing & Reasoning’).

 

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