Stars may look fixed and peaceful in the night sky, but they are constantly moving through space. In most cases, the distances between them are so enormous that direct collisions are extremely rare. However, under the right conditions, stars can collide or merge, especially in crowded regions such as the centres of galaxies or dense star clusters. A stellar collision happens when two stars pass so close together that their gravity causes them to interact strongly. Sometimes t

Stars are incredibly far away, and even the closest ones are far beyond anything humans could physically sample. So how do astronomers know what stars are made of without ever travelling to them? The answer comes from something that reaches us directly from the star: light. When astronomers collect starlight and pass it through an instrument called a spectroscope, the light is separated into its different wavelengths, creating a spectrum. This spectrum can look similar to a r

One of the biggest questions in astronomy is whether there is another Earth somewhere beyond our solar system. Thousands of exoplanets (planets orbiting stars other than the Sun) have already been discovered. Some are rocky, some are roughly Earth-sized, and some orbit at distances where liquid water might be possible on the surface of the planet. But finding a true “second Earth” is much more complicated than simply finding a planet that looks similar to ours. One of the fir

When we look at planets in our solar system, one thing becomes obvious very quickly: they are all roughly round. Earth, Mars, Jupiter, Saturn, and the others may differ in size, colour, and composition, but none of them are shaped like cubes, pyramids, or flat disks. So why are planets round in the first place? The answer comes down to gravity. ("President's Column #13: Flat Earthers and the rise of conspiracy theories" – Hokkaido University) Gravity pulls matter toward the c

Keeping a spacecraft in the right position is not always simple. Spacecraft are constantly affected by the gravity of nearby objects, such as the Sun, Earth, and Moon. However, there are certain locations in space where these gravitational forces and a spacecraft’s motion work together in a useful way. These locations are known as Lagrange points. Lagrange points exist in systems containing two large orbiting bodies, such as the Sun and Earth or Earth and the Moon. At these p

Most spacecraft travel through space using chemical rockets or other engines that require fuel. But what if a spacecraft could keep moving without carrying large amounts of propellant? One possible solution is a solar sail, a technology that uses sunlight itself to push a spacecraft through space. Solar sails work because light carries momentum. Even though photons, the particles of light, have no rest mass, they can still transfer momentum when they strike a surface. If a sp

On Earth, sunsets are usually filled with warm colors such as red, orange, and pink. On Mars, however, something surprising happens: the sky around the setting Sun can appear blue. This seems strange, especially because the Martian sky during the day is usually reddish or orange. The reason comes down to the planet’s atmosphere and the way its dust scatters sunlight. Sunset on Mars (NASA Science) Mars has a very thin atmosphere made mostly of carbon dioxide, but it also conta

At first glance, Enceladus looks like a small, frozen moon with little chance of being especially interesting. It orbits Saturn and is covered in a bright layer of ice, making it one of the most reflective objects in the solar system. However, beneath that icy surface lies something that has made Enceladus one of the most exciting places in the search for life beyond Earth: a hidden ocean. (NASA Science) Scientists discovered that Enceladus sprays enormous plumes of water vap

Getting into space currently requires enormous rockets, huge amounts of fuel, and extremely precise engineering. Rockets work, but they are expensive and technically demanding. For decades, scientists and engineers have wondered whether there might be another way to reach space. One of the most unusual ideas is the space elevator. (NBC News) A space elevator would work somewhat like an elevator on Earth, but on a much larger scale. Instead of travelling up a building, a space

Titan, Saturn’s largest moon, is one of the most unusual places in our solar system. At first glance, it may seem completely unsuitable for life. Its surface is extremely cold, its atmosphere is thick and hazy, and liquid water cannot remain on the surface. However, Titan has several features that make scientists wonder whether some form of life could exist there. One of the most interesting things about Titan is its atmosphere. Unlike most moons, Titan has a dense atmosphere

For centuries, humans have looked at the stars and wondered what exists beyond Earth. Today, space exploration is no longer just a fantasy. Scientists are discovering new planets, spacecrafts are traveling farther into the Solar System, and private companies are becoming increasingly involved in space missions. Celebrities are even making their first appearance outside of our atmosphere, but as our ability to explore space grows, so does an important question: Just because we

When you think of archaeology, you probably picture Egypt, not orbit. So what does it mean to uncover a satellite that never came home? Well, it generally means treating space as a place with history, not only a future. Aerospace Archaeologists explore cosmic history by studying the physical leftovers of the Space Age: spacecrafts, wrecks, orbital debris, and artifacts left in space. This includes the satellites that still circle Earth decades after going silent, the launch p

Neutron stars are already among the most extreme objects in space, but some are even more unusual. These objects are called magnetars, and they have the strongest magnetic fields known in the universe. Although they are only about the size of a city, their magnetic power and violent bursts of energy make them some of the most fascinating stellar remains astronomers have discovered. A magnetar forms after a massive star reaches the end of its life and explodes as a supernova.

Not every object in space fits neatly into the category of a star or a planet. Some exist somewhere in between. These unusual objects are called brown dwarfs, and they are often described as “failed stars” because they form like stars but never become hot enough to shine in the same way. Brown dwarfs usually form when clouds of gas and dust collapse under gravity. This is similar to how ordinary stars are born. However, a brown dwarf does not gather enough mass for its core t

Some of the brightest objects in the universe are powered by something that produces no light of its own: a black hole. These extraordinary objects are called quasars, and they can shine more brightly than entire galaxies despite coming from a relatively small region at a galaxy’s centre. A quasar is a particularly powerful type of active galactic nucleus, meaning an unusually bright and energetic centre of a galaxy. At the heart of it is a supermassive black hole containing

Most planets, including Earth, orbit a star. Their stars provide light, heat, and the gravitational pull that keeps them moving along a stable path. However, not every planet belongs to a solar system. Some worlds travel through space alone, without orbiting any star at all. These mysterious objects are known as rogue planets. Rogue planets, sometimes called free-floating planets, move through the darkness between stars. Because they do not receive regular light from a nearby

Movies often show spacecraft exploding with a loud boom or lasers making dramatic noises as they travel through space. In reality, outer space is almost completely silent. This is because sound cannot travel through a vacuum. Sound is created by vibrations. When an object vibrates, it pushes against nearby particles, causing them to move and pass the vibration along. On Earth, sound usually travels through air, but it can also move through liquids and solids. For example, sou

Sending humans to another planet is extremely difficult, expensive, and risky. Because of this, scientists often send robotic vehicles called rovers instead. Rovers can travel across the surface of another world, take photographs, study rocks and soil, and send their findings back to Earth. They act as mobile laboratories, allowing scientists to explore places that humans cannot yet safely reach. Perseverance Rover on Mars (NASA Science) Before a rover can begin exploring, it

Sleeping in space may sound peaceful, but it is very different from sleeping on Earth. Astronauts do not have beds, pillows, or gravity holding them in place. Instead, they sleep in specially designed sleeping bags attached to the walls of their spacecraft or space station. In microgravity, astronauts float rather than lie down. Because there is no clear “up” or “down,” they can sleep in almost any position. Their sleeping bags are secured so they do not drift around and bump

For most of history, astronomers studied the universe by observing light. Telescopes allowed scientists to examine stars, planets, and galaxies using visible light and other forms of radiation. However, there is another way to study the universe: by detecting tiny ripples in the structure of space itself. These ripples are known as gravitational waves. Gravitational waves are disturbances in space-time, which is the combination of space and time into one connected structure.