How Much Does a Shadow Weigh?

Today I will tell you Some Interesting Fact About Shadow in this blog:

I'm dam sure that we all love to have fun with hand shadows, but how much does a shadow weigh we think also about that?💪

I know it might sound like a silly question.😂

I mean, a shadow cannot be put on a scale and weighed. But, actually, the material that falls on top can be weighed. And we all knew that light has energy. In fact, when light encounters an object, it pushes that object just a little bit. 

On the surface of the earth, when sunlight is hitting it, every square inch is being pushed with a force of about 1 billion of a pound, which is basically nothing. But, over a large enough surface area, the results can be pretty fun. 

I have actually some examples:

• On a sunny day, the city of Chicago weighs 300 pounds more, simply because sunlight is falling on it and pushing it. 
• In outer space, where the solar wind isn't filtered by Earth's atmosphere or magnetic field, their results are also even bigger.
•  A spacecraft, traveling from Earth to Mars, would be pushed by light 1,000 km off course. So these things have to be factored into journeys to Mars. 

We've actually already created things that can sail with light:- giant reflective solar sails that are pushed by the Sun's light.

 

So, in a way that is calculable, though difficult to measure, an area covered by shadow is technically weighed less than the surrounding areas being pushed by light. But that is enough about the Sun. 

There are 3 astronomical bodies that can cast shadows on the surface of Earth bright and is enough for us humans to see and that we actually know about these:-  

• One is obviously the Sun 
• Moon
• But what about the third? Venus.

 

Pete Lawrence investigated this over a digital sky. Now, to make sure that the shadow that he saw was caused by Venus.

. 

He actually does the one thing i.e, 

he used a tube that could be pointed at specific regions in the sky. Inside the tube, he put a cutout shaped like the astronomical symbol for Venus. Now, here is light coming through the tube when pointed just adjacent to the Venus at a point in the sky relatively dark and empty to the human eye. 

But here is what came out of the tube when it is pointed at Venus -  Venusian Shadow. 

We all know that light travels quickly - 299,792,458 meters per second = c. 

But when this light coming off and enters into our eyeballs, is moving slightly slower than"c" because "c" is the speed of light in a vacuum, but all of this light if having to travel through a medium, in that case, air. 

And as we all knew that the speed of light in air is ever-so-slightly slower than "c"- 298,925,574 m/s. This is interesting because light travels more slowly through different materials, but "c" remains the universal speed limit, and as long as an object doesn't go that fast, it can still outpace light in a material. 

A charged particle, for instance, an electron, can travel through water faster than light happens, but never faster than "c". When this happens, we get something analogous to a sonic boom. We get a "Photonic Boom." 

You all were thinking that what is this sonic boom?

Actually, it is nothing but the sound information propagating off of the object is in the form of compression waves, and as the object gets closer and closer to the speed of sound, the speed that those waves are moving away from it, then each new wave has less time to get out of the way of the next, until eventually the waves collapse all into each other and the density and pressure are enormous, causing a sonic boom. 

Normally, when a charged particle moves through a material whose molecules can be polarized, the molecules give off photons. But each photon has room to fly away, and the waves all destructively interfere with each other, so no radiation is given off. But the faster particle when goes, the less room of the photons have away from each other and their waves begin to constructively interfere, giving off a photonic boom - "Cherenkov Radiation". 

Astronauts, especially those who have gone-the-way to the Moon, have reported seeing flashes of light. Many people attribute this to high-speed particles moving through the liquid inside their eye faster than light normally would, and it will causing photonic boom's on the right side inside their body. 

Speaking of the speed of light becomes a  great question for a few of you?😖 

It is nothing but it involves a possible way of going faster than "c". 

Let's say I want to push a button that is a lightyear away from me, which means that it would take light, 

the fastest possible thing in the universe, a year just to get from me to the button.

Ok...

 

When we think about these situations, we raise so many questions i.e,

• What happens if I built aboard, one lightyear long, all-the-way from me to the button, and then I pushed one end of the board? 
• Would the other end immediately push the button? 
• And if so, did I just break the speed of light?
•  Did I just send information faster than light?

Well, we're not talking about the speed of light anymore,

are we?

 

So, Actually, We are talking about the speed of push. When you push a rigid object, what you are really doing? you will only be putting a series of compression waves through the object, which moves at the speed of sound in the object's material. The information about "whoa, we've been pushed, you should move," is sent via that compression wave and it only travels at the speed of sound. So, when pushing a normal day-to-day size type object, it feels almost instantaneous. But when pushing a lightyear-long board, it would take a lot longer. A cool way to see this in action is to look at an object in which compression waves travel more slowly. 

But to wrap things up here's the point: 

The speed of push is not instant and it's certainly not the speed of light. But light can push you. In fact, technically, you weigh more when the lights are on then, you do when the lights are off.