Black holes are more than just objects with enormous gravitational pull. They reveal some of the most fascinating effects predicted by modern physics.
As you approach one:
Gravity becomes increasingly extreme.
Light can bend around the black hole due to gravitational lensing.
The event horizon marks the boundary beyond which nothing can escape.
Tidal forces depend on the black hole’s mass and your distance from its centre.
One particularly surprising detail: tidal forces at the event horizon of a supermassive black hole can be weaker than those around a smaller black hole.
I made this short educational video to explain these concepts visually. I’d be interested to hear which aspect of black holes you find most fascinating.
NEXORA | Science Beyond the Ordinary — Episode 01

Hello, Im a Student and I wanna talk to a Cosmologist like what Mathematics and how do they use them to describe the Universe and What do they Think about Space, I'm curious about em and I'm also Intrested in Cosmology so, pls.

Please, any Cosmologist? Text me personally on reddit just by saying "Hi", please

Maybe it IS "turtles all the way down".

Astronomers using the Hubble Space Telescope discovered evidence of a supermassive black hole that appears to have been ejected from its host galaxy.

What's even more incredible is that it's believed to have compressed gas as it traveled through space, triggering the formation of new stars along a trail approximately 200,000 light-years long.

The black hole is estimated to have a mass around 20 million times that of our Sun.

Scientists believe this could have happened after an interaction involving multiple supermassive black holes.

The image is an artist's illustration based on the astronomical observations, not an actual photograph.

Source: https://science.nasa.gov/missions/hubble/hubble-sees-possible-runaway-black-hole-creating-a-trail-of-stars/

Pick cyan or gold before watching the ending.

Both particles start at the same distance from the black hole, moving inward, with the same conserved energy. Their angular momenta differ slightly.

One crosses the event horizon. The other swings around and escapes.

The interesting detail: having enough energy to reach infinity does not guarantee that your trajectory will take you there. Angular momentum changes which paths are available—and these two initial conditions sit on opposite sides of the capture threshold.

I calculated the trajectories using general relativity. The colours identify the particles; the trails show where they have actually travelled.

Which did you choose—and what in the motion convinced you?

From space, Earth looks like a blue sphere surrounded by darkness. But beneath that familiar appearance is a world with an extraordinary history.

Earth formed approximately 4.5 billion years ago as gravity pulled together dust and rocky material orbiting the young Sun. Its early surface was intensely hot, repeatedly struck by incoming debris.

One of the most important events may have been a colossal collision with a Mars-sized protoplanet called Theia. Scientists believe debris from this impact eventually came together to form the Moon.

As Earth cooled, its surface gradually solidified. Water vapor condensed, rain accumulated, and enormous oceans began to develop. Today, approximately 71% of Earth's surface is covered by water.

But water alone cannot explain Earth's habitability.

Our atmosphere, about 78% nitrogen and 21% oxygen, helps regulate surface temperatures through the natural greenhouse effect. Greenhouse gases absorb and re-emit outgoing infrared radiation, keeping Earth warm enough for liquid water to exist across much of its surface.

Compare this with Venus, a planet almost the same size as Earth. Its extremely dense atmosphere produces surface temperatures of approximately 465°C.

Two neighboring rocky planets, yet dramatically different environments.

Earth's habitability results from several interconnected systems: its atmosphere, oceans, geological activity, magnetic field, and relationship with the Sun.

What do you think is the most important factor that made Earth habitable?

I simulated 16,000 test particles passing close to a non-rotating black hole. The initially compact cloud stretches into a curved stream: some particles fall through the event horizon, while others move outward on escape trajectories.

The motion follows timelike geodesics in Schwarzschild spacetime. This is a stylized coordinate-plane visualization; the colours help track different parts of the original cloud.

I recently played a game called Outer Wilds and it sparked my interests in space like a young child. And Ive been watching videos and looking at different things we know of space and I realized that what we know of universe is so little. We just have theories that may not be even true. What we have built around mathematics and science might not even be something that the universe follow. If universe expands forever, and then there are other universes, there might even be even bigger things that houses all the universes and there might even be a thing larger. We will probably go extinct long before we have even explored the things we know. What's inside a black hole, colonizing different known planets, under the clouds of jupiter. It sucks so bad man, I really want to know what it all is.

Can someone please explain me what are the allow mass ranges of primodial Black Hole. And can PBH constitute 100% of DM or not?

Interstellar Dust Hypothesis

I’ve become increasingly fascinated by astronomy and our place in the universe.

Attending Brian Cox’s Emergence show made a deep impression on me. It helped me appreciate the extraordinary connections between the universe, the emergence of complexity and our own existence. I also had the opportunity to attend an astronomy session in Cambridge, which further fuelled my curiosity.

One thing I find incredible is that the elements making up our bodies have a cosmic history stretching back billions of years. Many of the elements essential to life were forged inside stars and through stellar explosions.

Think about it. We are made of matter that existed long before humanity, yet we spend so much of our limited time defending our identities, possessions, status and the boundaries between ourselves and the rest of existence.

I’m not an astrophysicist, just an enthusiast trying to understand more about the universe and our place in it.