Archive for the ‘Everyday Science’ Category

This Strange Quantum World

August 11, 2009

I could never get this stuff in University, so I am so glad I ran across this video. Astronomy deals with a lot of different particles, so it is good to know how do they behave. Apparently their behaviour is quite (I mean completely!) different from what we got used to in our macro world.

Everything seems to be connected in our world. Einstein’s genius for example connected mass and energy in one simple formula. We also know that time and speed are connected: the faster you move the slower your clock ticks. Mass and velocity are linked as well, the faster you move the more energy is required to speed you up, it means you are becoming heavier. Particles seem to combine properties of usual physical objects with properties of waves

With research of particles we discovered that those solid balls (that’s how I always imagines protons, neutrons, electrons and other particles) behave like waves — curving behind the obstacles and interfering with each other. The simplest example is light: sometimes it behaves like a beam of particles (photons) and that’s how we explain that light generates preassure, sometimes light acts as a wave as it allows us to focus our backyard telescope. We also discovered a very strange thing about particles — if you watch them they behave differently than when you don’t watch them. This is very odd, but I think we just don’t get some simple nature law to explain it yet. This video talks about particle behaviour in simple words, well worth watching:


Why Do We See Visible Light?

July 24, 2009

Electromagnetic waves range from radio waves to x-ray and gamma rays. The tiny fraction of all spectrum we can see with our eyes. Did you ever ask yourself why do we see exactly this range of electromagnetic waves?

To answer this question let’s think about why do we see anything at all. Different objects around us have different texture, shape and colors. Most of objects do not emit light on their own, they just reflect the light from the light source. The way they reflect and the type of light they reflect gives us information about texture, color and shape of the object.

Currently we have a lot of different light sources, but most of the human evolution history there were only few of them. The most important one is our Sun. Sun shines, objects reflect Sun’s light and we see the reflected light. For your information Sun shines in ultraviolet (we get tan and skin cancer sometimes thanks to it), Sun shines in visible light (this one we know for sure :-) and Sun shines in infrared (that’s why you feel warm when Sun shines on you). The thing is, Sun shines differently in different wave lengths and also our atmosphere absorbs electromagnetic¬†waves differently for different wave lengths. Below is the Sun spectrum with and without atmosphere:

Sun spectrum with and without atmosphere. Image from:

Sun spectrum with and without atmosphere. Image from:

As you see most of the solar energy comes to us in the form of visible light, so our eyes adopted to it. One thing bothers me though, you can see from the picture that energy maximum is somewhere near the blue color and our eye is most sensitive to the green-yellow light. Why?

How Science Mind Works

July 20, 2009

This post is not about Astronomy only, but the general science approach to all things. I promise I wouldn’t write too many of such posts, but it is a personal blog, and there are some things ¬†I want to share with others.

Talking to people I noticed that those who are far from science think in a very different way then I do, so I decided to explain how scientists think and study the world around us. If you are not into science you could notice that sometimes it’s hard to explain something to the stubborn sceptic, but the truth is if you do believe strongly in something it does not make it proved in scientific mind, the way scientific mind works is different.

This is a hollywood mad scientist stereotype. Image from: wikimedia

This is a Hollywood mad scientist stereotype. Image from: wikimedia

First we observe something around us. Let’s say we see how apple falls from the tree. What do you think when you see it? Probably “m-m-m ripe apple” or something like this :-). What does scientist think? “Why did apple fall down?” most likely. After observation comes the hypothesis. You can think of any possible reason for apple to fall down — they all will be hypotheses. Let me come up with some. Apple felt down, because:

  1. It is July, apples always fall down in July
  2. I was thinking of apple just 1 hour ago, if you think of apple really hard then one falls down from the nearby tree
  3. All bodies with mass attract to each other

Now we have three different hypotheses. At this point of research all of them are equally true. This is how science mind works, it’s trying to be objective. I will not tell you that first two are total absurd, because I don’t have any proof of it yet. When they say that some scientists are stubborn and close minded, it all comes from the lack of evidence. Scientists are very open minded, they love to believe that there are aliens out there and sunk Atlantis on the ocean bottom, but they don’t say it, because they don’t have evidence of it, that’s all. They will be very glad to find one, so instead of trying to convince a science man, give him evidence and he’ll agree with you right away.

And this is how "average" scientist looks like :-) Image credit: NOAA

And this is how "average" scientist looks like :-) Image credit: NOAA

The next step is to convert hypothesis to theory. We do it by predicting something. That’s the real key to how science works, so pay attention if you did not fall asleep yet. If you have a bunch of already known observations and just tie them together with some fancy story it is not proving, it is creating hypothesis. To prove hypothesis one should predict something unknown by now. In our simple “apple falls from the tree” example we could do this:

  1. Find another apple tree and wait till next August to see if apple will fall. In this case we are predicting apple fall for the next year. It didn’t happen yet, so it is a true prediction.
  2. Think “apple” real hard near another apple tree and see if it makes apple fall down. Here we predict apple fall by will. You can say: apple will fall down tomorrow at 3 p.m. because I will think really hard about it, it didn’t happen yet, so it is a true prediction.
  3. Take two bodies with mass and check out if they attract to each other. Let’s assume that we don’t know gravitational law here, so there’s no way we can know that there is a force between a chair and a hm… table ;-) So it is a real prediction, we predict something to happen while we don’t know if it will really happen.

After first two predictions fail and the third one works, the third hypothesis is promoted to theory. While hypothesis are not so important (you can create thousands of them easily) theory is something really valuable (remember it allows us to make predictions!). So, it’s the theories we fight for and it’s them who allows us to launch spacecrafts, because we know that any two bodies with mass attract to each other and how they attract. Now let’s give a credit to those who can figure out gravity laws from observing falling apples :-)

They say this guy discovered gravitational law when apple hit him in a head. Image from:

They say this guy discovered gravitational law when apple hit him in a head. Image from:

While scientific method I described works fairly well, no one can say that it is the best way to explore the world around us, we just did not come up with a better one yet (or maybe somebody did came up, but forgot to tell the others ;-).