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Black hole event horizons are real, new evidence suggests

  • Astronomers have shown that matter likely disappears after entering a black hole, refuting an alternate theory that matter is destroyed by colliding into a hard surface in space.
  • It’s a big deal because humanity hardly understands what black holes really are. Hollywood has incorrectly envisioned them as “cosmic vacuums” or separate time-traveling dimensions, and they’re still a mystery to the fleets of scientific labs studying them.
  • As it stands, two prominent theories describe what happens to stars in space. One is the “event horizon” theory, which argues that matter essentially gets sucked up into black holes and then vanishes.
  • Event horizons are basically a boundary around a black hole that is literally inescapable. Their force of gravity is so strong that nothing — including light — can escape it. Read more (5/31/17)

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Catching prey using Vortices

I was reading about Vortices and after hours of research online, out of the blue I stumbled upon this amazing bird. This is the Red Necked Phalarope and from the looks of it seems to have put vortices to a really productive use - catching its prey.

By rotating around ~60-80 times a minute, it produces an upward vortex that sucks out insects/bugs/crustaceans from the water, which it swiftly picks up with its beak and eats. ( This one would have aced the Fluids class for sure :D)

This is analogous to tornadoes sweeping up cars and houses along its way in an upward swirl.

Mind Blown!

** The actual dynamics of vortices of course is waay more complicated. ;)

*** There are three species of phalarope (red-necked, red/grey, and Wilson’s), and they can all feed like that.            

The simple harmonic oscillator

Anonymous asked: Please explain the intuition of solving the SHM equation.

Okay Anon! Here you go, this is my rendition.

The problem

You have a mass suspended on a spring. We want to know where the mass will be at any instant of time.

Describe the motion of the mass

The physical solution

Now before we get on to the math, let us first visualize the motion by attaching a spray paint bottle as the mass.

Oh, wait that seems like a function that we are familiar with - The sinusoid.

Without even having to write down a single equation, we have found out the solution to our problem. The motion that is traced  by the mass is a sinusoid.

But what do I mean by a sinusoid ?

If you took the plotted paper and tried to create that function with the help of sum of polynomials i.e x, x2, x3 … Now you this what it would like :

By taking an infinite of these polynomial sums you get the function Since this series of polynomial occurs a lot, its given the name - sine.

I hope this shed some light on the intuition of the SHM equation. Have fun!

Around 6 million years ago, the African and Eurasian plates moved together, cutting the Mediterranean Sea off from the Atlantic. Without an influx of water from the Atlantic, evaporation began removing more water from the Mediterranean than rivers could replace. The sea dried out almost completely over the course of a couple thousand years.

About 5.3 million years ago, the Straits of Gibraltar reopened, creating a massive flood into the Mediterranean known as the Zanclean Flood. Water rushed down the straits and into the Mediterranean at speeds as high as 40 m/s (90 mph). At its peak, the Zanclean Flood is estimated to have reached rates 1000 times greater than the volumetric flow rate of the Amazon River. 

A similar breach flood occurred in the Black Sea within the past 10,000 years when the Bosporus became unblocked. That flood likely had a devastating impact on Neolithic societies in the area and may be the inspiration for the floods described in the Epic of Gilgamesh and the Bible. (Image credit: BBC, source)

Yes, sure its fun to see a lady spin around like that, but I had one of my friends ask me - “Where do you even use this mate?”

Here’s one application that I know very well off.

Spin Stabilization

If you have ever seen a rocket launch, you might know that sometimes the rockets are given a spin while launching. This is known as spin stabilization.

Basically, the rotational inertia of the rotating body will stabilize the rocket against any disturbances and help maintain its intended heading.

The same principle is used in rifling of firearms as well. **

YoYo DeSpin

Okay, now there is the question how to “De-spin” the rocket:

Well, you do what the lady does: stretch out your arms and you will slow down !

The rocket has weights connected to a cable that stretch out and almost immediately the rocket slows down. This maneuver is known as the YoYo DeSpin. ( Damn good name ! )

All thanks to the conservation of angular momentum !

Have a good one !

* Another method to stabilization : 3-axis stabilization

** Bullets spin stabilization - post

** Source rocket launch video

Why does a Popcorn pop?

Be it a movie theater or at the comforts of your couch, the popcorn is definitely a favorite snack among all age groups. But why does it pop?

Popcorn is no ordinary corn.

Of all the different types of corn out there, Popcorn is the only variety that pops, hence the name.

There is a tiny droplet of water inside the kernel of a popcorn, which is surrounded by a hard shell called a hull.

As the popcorn is heated, the water turns into steam. This builds pressure inside the kernel. When the pressure built cannot be contained by the hull, it POPS!

And a Popcorn is born.

For a popcorn to pop successfully, the ideal amount of moisture must be between 13- 14 percent.

When there is too little moisture, there will not be enough steam produced to carry out the popping and if there is too much moisture, the popcorn will crack prematurely.

Sometimes the most simpleton questions can have the most elegant answers. Ergo Stay Hungry, Stay Foolish!

Have a great one!