Space holds a vast, unimaginable scale of celestial bodies and cosmic events, with many of these being out of our reach and not yet fully understood (at least for now). Nevertheless, there are many interesting phenomena which have made their way to our studies and into science fiction. Here are our top picks.
Criteria: to qualify for our list, we will be judging entries based on their real-life existence or theorised existence, and will not be looking at any fictional concepts.
10: Supernova
A Supernova is a large cataclysmic explosion that occurs when a star reaches the end of its life, releasing large amounts of energy and matter into space and elements, such as carbon, oxygen, iron, and many others that in turn is responsible and crucial for the formation of new stars, planets and life. These explosions can be so bright that they can even outshine whole galaxies and last from a few weeks to months. Supernova’s are extremely important in the scale of the universe and they are responsible for many of the phenomena on the list. There are two types of classification of a Supernova but the most commonly known is a Type II supernova in which a star exhausts its nuclear fuel, without the outward pressure from fusion, the star’s core collapses under its own gravity, leading to a rapid implosion with the outer layers that rebound off the core, creating a powerful shockwave that leads to a massive explosion.
9: Cosmic Microwave Background (CMB)
Cosmic Microwave Background (CMB) radiation is one of the most important pieces of evidence we have for the Big Bang theory and provides a snapshot of the early universe – direct observational data for the early universe’s hot, dense state. It is a form of electromagnetic radiation primarily residing in the microwave part of the spectrum that spans all of space, representing the residual heat left over from the Big Bang. The origins of the radiation is said to date back to a few hundred thousands years after the Big Bang when the universe had cooled enough for electrons and protons to combine into neutral hydrogen atoms, this process then allowed photons to travel freely through space, creating the CMB we observe today. It was first discovered in 1965 by Arno Penzias and Robert Wilson who were conducting radio astronomy experiments and detected a background noise that couldn’t be explained or identified by any terrestrial sources. This observation aligned with predictions from cosmologists who suggested that the early universe would have left behind a thermal radiation signature, thus confirming the existence of the CMB.
8: Exoplanets
Exoplanets are planets that orbit stars outside our solar system. Their discovery and study have revolutionised our understanding of planetary systems and have opened the possibility of finding life beyond Earth. They can be categorised by size and composition with a few of these including Hot Jupiter’s, Super Earths and Neptune-like/Ice Giants. They are quite difficult to locate as the stars they orbit usually outshine them with the first one being discovered in the 1990s but thousands have been discovered since then through various methods such as direct imaging, radial velocity, and transit. Exoplanets could essentially provide us with answers to other life in the universe, if these planets hold similar composition and conditions to that of Earth then it is possible they may support life on them. Such experiments are conducted by astrobiologists who study these planets closely to allow the understanding of how habitable they are.
7: Dark Matter
Dark matter is a bit of a debated, and not yet completely understood, form of matter that is invisible and undetectable through conventional telescopes . It is invisible in the sense that it does not emit, absorb, or reflect light nor does it interact with any form of electromagnetic radiation but does interact with gravity – exerting gravitational forces on visible matter such as galaxies. Despite being unseen, it has a significant influence on the structure and dynamics of the universe and is said to make up about 85% of matter in the whole universe. Dark matter can be attributed to a few cosmological observations that couldn’t be explained by visible matter alone. This includes galaxy rotation curves where it was identified that outer regions of galaxies were rotating much faster than expected based on the visible mass alone, this suggested the presence of additional unseen mass – dark matter. Experiments like those at the Large Hadron Collider (LHC) aim to produce dark matter particles through high-energy collisions, providing another potential method of detection. A better understanding of dark matter would see fundamental questions about the universe answered and insights into the laws of physics.
6: Pulsars
Pulsars are a type of neutron star produced through ongoing rotation which then causes their magnetic fields to emit intense beams of radiation that spin incredibly fast, typically in the form of radio waves, but sometimes extending to X-rays or gamma rays. When these beams are directed toward Earth, they create regular pulses of radiation, which can be detected by radio telescopes. They mimic a sort of lighthouse light beam effect and this pulsating is where they get there name from. The first ever pulsar was discovered in 1967, which also provided evidence of the existence of neutron stars.
5: Quasars
4: Nebula
An image taken by the Hubble Space Telescope of the Cats Eye Nebula. Nebula’s are large clouds of gas and dust within which many stars are born. There are many types of Nebulas in space; some of these shine exceptionally bright due to ionisation of their gas by the stars within, and others known as dark nebulae have dense clouds of gas and dust that block light from objects behind them, making them appear as dark patches in the sky. Nebulas have different names usually to match their looks, some of these include the Helix nebula, Crab nebula, and Orion nebula. Nebula’s are important to understand the birth cycle of stars and how planetary systems are formed and evolve over time, by analysing the light, scientists can study their composition.
3: Gamma Ray Burst
Gamma-ray bursts (GRBs) are the brightest phenomenon in space to ever occur, releasing the same immense amount of energy in just a few seconds that some stars release in their lifetime. Some of these can last for less than 2 seconds (known as short duration GRBs) and these are usually linked to the death of stars from supernovas while others over 2 seconds are long duration GRBs and are associated with neutron star merger and black holes. A famous GRB in 2008 known as the “naked-eye” GRB, was so bright that it could be seen with the naked eye despite being located 7.5 billion light-years away.
2: Wormhole
Wormholes are hypothetical passages or “space tunnels” that allow one to travel through time in one point in space to another. Also known as an Einstein-Rosen bridge, they are essentially solutions to the equations of general relativity proposed by Albert Einstein and Nathan Rosen. Wormholes have never been observed and are only theorised concepts. Wormholes fall into two categories which are traversable and non-traversable, the former are wormholes which would allow matter to pass through instantly and the latter being wormholes that are not stable enough for any traversal. The realisation of such a concept would allow for faster than light travel and revolutionise space exploration. Wormholes have been explored in pop culture, particularly within Sci Fi and continue to be discussed and studied indirectly, such discoveries could allow great advancements in physics.
1: Black Hole 
The ellusive and deeply captivating phenomena that is the black hole. Black holes hold a lot of speculation and have been popularised also by literature and modern media as space phenomena associated with total death or the end of the universe. The appeal also comes from not knowing what lies beyond them, popular theories include portals to other parts of space or even dimensions, time tunnels and one that we all hope is not true, eternal nothingness. Black holes are born when dead stars collapse and then begin pulling in matter after they have exhausted their nuclear fuel. Supermassive black holes are also another form of black hole that are found at the centre of most galaxies that have theoretically grown by just pulling in mass over the years. They are one of the easier phenomenon’s to encounter due to them bending the light that surrounds them and the gravitational forces. Black holes have a boundary surrounding them that’s known as an event horizon, it marks a point of no return, where nothing can escape it once it enters that boundary. It is believed that once something enters a black hole, its condensed infinitely and is distorted by time, essentially not even time survives inside one as anything inside would just come to a standstill in a sort of frozen state – a horrible fate indeed.
Honourable Mention: Asteroid
Asteroids are small bodies of rock that orbit the sun and are one of the more well known spacial object’s that the general population is aware of and probably not for good reason. Asteroids are often associated with destruction and the end of the world, often explored in film and TV, an asteroid is also long thought to be the cause of the extinction of the dinosaurs 65 million years ago. Asteroids have irregular shapes and vary in composition and size – from dust particles to almost 1000 kilometres across. The asteroid belt located in between Mars and Jupiter contains a large amount of asteroids, they are early remnants of the solar systems creation that never materialised into celestial bodies.
Other Contenders
White Dwarfs: The remnants of low-mass stars after they have exhausted their nuclear fuel.
Solar Flares: Explosive releases of energy from the Sun’s surface, often causing disruptions to Earth’s magnetic field and communications.
Elliptical Galaxies: Galaxies with an ellipsoidal shape, lacking the distinct spiral structure of spiral galaxies. They often contain older stars and less interstellar matter.