A Tidal Boat Dance πŸŒŠ

Compiled by Reddit User u/Spiritgreen from Hall’s Harbour webcams
(Right click on video and select “loop” while playing to continuously loop)

The above GIF shows the changing tides in a unique manner, by splicing together pictures taken throughout an entire day, at 20 minute intervals! The resulting effect is that it looks as if time is spiraling around the image. You can also see both pairs of high and low tides, one set during the day and one set during the night.

Unless you’ve lived by or frequently visited shores, you’ve probably never had to think about the tides much. Sure, the concept of tides is fairly well known by many, but how much of a difference does it make?

Well, as the video shows, quite a lot! Before I had watched time-lapses of tidal behavior, I had assumed that the water level difference between high tide and low tide wasn’t more than a meter or so. The reality is that in some places, like at Hall’s Harbour in Nova Scotia, Canada, the difference can be up to 14 meters! The rate at which it rises is about 2.5 centimeters a minute, escapable unless you were wading far out at sea.

After realizing how much more water is present in one area at high tide, I got to thinking. Where does all the water go when it recedes? Surely it can’t just… disappear? Then, I realized that at any one point in time on Earth, if it is high tide somewhere, then it is low tide elsewhere. So, the water is pulled towards those continuously moving (at least, relative to the surface of the Earth) points at which high tide exists, and thus, low tide exists.

Thankfully, there aren’t mystical forces drinking the ocean up away from shores, or we’d have bigger problems to deal with.

Another thing about tides that I didn’t know about until just a few days ago was that yes, the moon causes tides, but in what way? It turns out that tides are caused by the magnitude of the difference in gravitational force felt on opposite sides of a body, not necessarily the magnitude of the forces themselves. I had always accepted that the Moon’s gravitational force somehow caused tides since that’s what I was told since I was very young, but I also figured that the gravitational force on the Earth from the Sun must be stronger than the Moon’s, or we’d probably crash into the Moon. I had never put two and two together, and wondered why it was the Moon that caused much larger tides, even though the Sun pulls the Earth with much greater force.

The secret is that gravitational force drops proportionally to the square of the distance from the object, so the difference between gravitational force felt at two points separated by a constant distance is higher when they are closer to the massive object than if they were farther away. In this case, the two points are opposite sides of Earth, and the objects causing a force to be felt are the Moon and the Sun.

It was thanks to a recent Astronomy homework assignment that it was made apparent to me! See, you really do learn things in school. πŸ˜‚ I’m looking forward to the next astronomical epiphany, but until then, enjoy this spiraling tidal time-lapse! 🌊

Feeling Dizzy Yet? πŸ’«

This isn’t your everyday Milky Way time lapse video.

Video Captured by Eric Brummel

This video, captured by Eric Brummel, is sky-stabilized with the Earth in view to show our planet’s daily rotations.

It’s amazing, isn’t it?

We don’t think about it often during our daily lives, but every single second, we’re moving vast distances across space. Your glass on the edge of the counter or the monitor you’re reading this blog on might seem motionless, but in reality, we’re spinning around at a speed of about 460 m/s (approximately 1,000 mph), and that’s only counting Earth’s rotation!

If we were to factor in our actual orbit around the Sun, we’re moving at about 30,400 m/s, and if we were to factor in the solar system’s orbit in the Milky Way galaxy, about 220,000 m/s!

How come we can’t feel this motion though? To me, I’m only sitting back, enjoying the peace and quiet. That’s because everything on Earth is rotating at the same speed as us, including the atmosphere, the buildings, and the glass on your counter. Everything has been spinning ever since the Solar System was formed out of a collapsing dust cloud, and it’s never stopped since. We’d only feel it if Earth suddenly stopped, like if a car suddenly stopped. Just thank inertia for keeping your drink on the table.

When we look up at the sky and see the Sun rise, then later on, set, or the stars travel overhead, it can be easy to forget that we aren’t stationary and that our own planet’s rotation and orbit around the Sun cause these objects to move relative to us. To an outside observer’s perspective, we may as well be flying through space at incredible speeds on a wobbling top, which sounds more fun anyways.

Enjoy the rest of your orbit around the Sun! 😊

Meet (Astrono)me! ⭐

by me

Thank you for visiting my blog! 😊

Hello! My name is Vivian Li, and I’m just now starting my blog about my studies on the solar system this upcoming semester.

I’m a junior undergraduate student in Vanderbilt University, and looking forward to great things this semester in ASTR2110!

Though I’m a computer science major and pursuing a minor in mathematics, I’m taking this astronomy course to learn more diverse topics during my time in college.