Looking Into the Past

When I started this blog I sought to share with everyone what might be considered "weird science". Not weird because it's not true, or it was discovered in some strange fashion but because the conclusions it gives us are not easy to accept into our daily lives.

The fact that the measured speed of light tells us that we are often looking into the past is one of those.

Let's start with some easy examples:

The Moon

The Moon is approximately 400,000 km (the amount of kms most cars end up going in their lifetime!) and speed of light is about 3 m/s, so the time it takes light to travel between Earth and the Moon is: 1.26 seconds.

So..if the Moon blew up, we wouldn't see the explosion for 1.26 seconds


The Sun

The Sun is about 150,000,000 km (no car can put that much on it's engine, not even a Honda) away from Earth. 

So ..if the Sun blew up, we would still see the Sun up in the sky for about 8.3 minutes

Everything Else

Just recently I talked about a famous image from the Hubble space telescope containing thousands of galaxies. Now, if we apply the concept above to these images we get an astounding conclusion:

The stars and galaxies we are seeing in all of these images are actually in the past, not a few seconds or minutes..but years and years into the past:

As you can see from the image above the further out a telescope captures an object the further back it is in time as far as we can see (i.e almost a billion years).

Basically the light waves from that object took a billion years to reach us, so we have no idea what it's current state is and we wont know for another billion years.

Just another example of #Scale.

Always in the Past

My final thought that I want to leave you with is this. If light travels at a certain speed and is not instantaneous, does this mean we're always seeing things in the past? The simple answer is yes.

But, it's so fast that for all intents and purposes it's instant (nanoseconds). Still something to think about when you see your friend waving at you from a distance...

The Moon.

Striking isn't it?

We've all seen it, the gigantic, ominous, orange orb floating near the horizon that we all crane our necks to catch as it hides behind tall buildings while we run about our busy nights. Many question how this is possible but few ever get a chance to answer that. 

In about 10 minutes or less I will try my best:


The Moon Illusion

So if you're curious about this you're in pretty good company - the first man to be puzzled by this was Aristotle way back in 400 B.C.

He figured it had something to do with the atmosphere considering you're seeing the moon through a lot more of the atmosphere when it's at the horizon:

Figure 3.14 - Artist's (my) depiction of possible atmospheric effects | NOT drawn to scale. At all.

He figured it was causing some sort of magnification but that wasn't true, although it did account for half of our illusion: the orange hue. Similar to the sun that looks like a delicious egg yolk close to the horizon the moon also looks more orange.


The Answers (maybe...)

Both objects
are exactly the
same size

There are two main explanations for the illusion.

The first is the Ponzo Illusion. Basically our brains through evolution over the years have developed several shortcuts. This one tells us that due to perspective, towards the horizon things are more far away (i.e as the lines converge).

Therefore, if two objects look exactly the same at the horizon and nearer to us, then the one near the horizon must be bigger. 



The second half of this explanation is the Ebbinghaus Illusion, more commonly known as "Wow, my car looks huge next to that smart car!". This one's pretty simple, when the moon is next to the horizon it's passing by other objects unlike when it's up in the sky, giving our brains a frame of reference and therefore enlarging the size of the Moon.


The p(i)lot twist!

Sounds pretty legitimate? I thought so too, UNTIL I read that the illusion is experienced even by airline pilots flying far enough that they don't have the same reference objects that we do.

What does this mean? Well it's just one of many unexplained scientific mysteries that continue to remind us of how complex and challenging nature can be.


Fun with Moon illusions

In closing I figured we all deserved a fun set of moon illusions rather than such difficult to understand and scary looking ones. My favorite is definitely the "moon painting".