Answers to common questions about the Universe and the world we live in.

Why is the sky blue?
Why is grass green?

I'll keep updating this blog over time, expect answers of 2-3 sentences to questions that may have crossed your mind many times before. Thanks, Adam King. X

The sky is blue due to the interaction of photons that have travelled the 8 minutes to the Earth from the Sun. They are being absorbed by the Oxygen in our atmosphere, however, the BLUE photons are being re-emitted/reflected and that is why the sky is blue.

You can take this fact and apply it to anything with colour!! If something is red, it is emitting/reflecting RED photons.

Grass/plants are GREEN because they use red and blue photons as energy for photosynthesis but reflect GREEN - this is probably due to the GREEN photons being of no use to them. I think they are spectacularly clever and GREEN is a nice colour - on a plant of course :-D. X

THE SUN IS WHITE! Yes, its true! It only appears yellow because we are observing it through our atmosphere. If you were to somehow view the Sun in a vacuum - it would be white. Why is it white? Well, visible light that has been "split" by a prism shows all the colours of the rainbow but if you use another prism the light essentially comes back together and when this happens - it is WHITE. All the colours of the rainbow together are WHITE. You look at the night sky when it's clear and you see many many stars and they are white. The Sun is a star and it's white too!! X

Why are Sunsets' RED? Well, if you've read the answer above as to why the sky is blue then this will make perfect sense. As the Sun sets on the horizon it appears to get lower in the sky because of the Earths spin and we are heading for night-time where we are on Earth at that time. Due to the Sun being lower on the horizon, the photons (light) will pass through more of the Earths atmosphere and encounter other gases such as pollution and perhaps water vapour. This results in the scattering of RED light predominantly, hints of orange are there too. So basically its all about YOUR position on the Earth and fundamentally, what is YOUR SUNSET is someone elses SUNRISE. X

Why are stars and planets spherical-shaped?
Gravity is the cause. Gravity is responsible for "building" every galaxy, star, planet, asteroid  and comet. If I gave you a bunch of rocks and instructed you to "squash" them all together at the same time or told you that you had to make these rocks as small and compact as possible, you would proceed to wrap your hands around them and squeeze. You would form a sphere with your hands as you crushed the rocks. Gravity forms rocks into spheres because it is the only shape in which MASS can be evenly distributed. Think about it for a second.........you wouldn't see a square planet or a pentagon planet would you? It would have edges and be uneven. MASS is evenly distributed throughout a sphere and therefore it is BALANCED. If something is BALANCED it is in a suitable state. Stars are born due to gravity forcing atoms of Hydrogen together yet the resulting nuclear fusion causes outward pressure that is almost equal to the crunching of GRAVITY. The star is BALANCED. The Earth is actually referred to as an OBLATE SPHEROID - it isn't perfectly spherical - it BULGES at THE EQUATOR.

Answers to questions.

Leave me a scientific question which I'll endeavour to answer. Write your question in my comments section and I'll answer it here and quote your name, thanks, Adam :-) Much love. X

The four fundamental forces of the Universe

Another blog I'm gonna adore!!

Yes, four fundamental forces are responsible for making the Universe what it is and these forces are enabling YOU to READ this right now.

Here they are (strongest =1, weakest=4):

1.Strong nuclear force
2. Electromagnetic force
3. Weak nuclear force
4. Gravity

Gravity is the weakest and the weakest by far - planet Earth is pulling everything around you down towards it, got a pen? Pick it up!! Gravity isn't so strong is it! However, the Suns gravity keeps Earth in orbit around it so it must be formidable! What if I told you that Gravity is both the creator and the destroyer? If Gravity is all about attraction, then why doesn't everything just come together instead of spread apart all over the Universe? The answer - it's too weak to overcome the other forces - atleast for now.

Here is aquick break-down of the strength differences. I've given Gravity no rating but instead the numbers reflect how much stronger the other forces are compared to gravity. the number in brackets is how many zeros after 10 there are.

1.Strong nuclear force 10(-38)
2. Electromagnetic force 10(-36)
3. Weak nuclear force 10(-25)
4. Gravity

Let's begin with the strong nuclear force - this is CRUCIAL and without it - no other force would exist. If you've read my post on the ATOM then you will know that the atomic nucleus contains protons and neutrons. Well the reason that they are BOUND together in the nucleus is due to the STRONG NUCLEAR FORCE. The strong nuclear force binds together the QUARKS inside the protons and neutrons (remember NUCLEAR FUSION) Each of the forces has a MESSENGER PARTICLE which basically represents the presence of the force, it is also known as a MEDIATOR (think MEDIUM - in-between). the MESSENGER for the strong nuclear force is the GLUON (easy to remember as GLUE).

Here's a pic:









This is a PROTON! You can see that the "wavey lines" are the GLUONS.

There is a second part to the STRONG NUCLEAR FORCE which I wanted to write about and that is the RESIDUAL STRONG NUCLEAR FORCE - the strength is the same but the MESSENGER PARTICLE is not. The messenger particle is the PION and the PION is responsible for binding the PROTONS and NEUTRONS together inside the ATOMIC NUCLEUS. This force stops the protons and neutrons from pulling apart from each other. PIONS are generated when the protons and neutrons try to move apart.

LASTLY, what is very important to understand is the RANGE of the force and by this I mean what is the distance at which this force can work. How close of a RANGE does the force need to work and can the RANGE be vast. The atomic nucleus and the distance between the QUARKS is majorly small (the diameter of a proton is 10^-15 m and the the distance between a proton and a neutron is the SAME. The strong nuclear force only works at a very very very small range.




THE ELECTROMAGNETIC FORCE:

This force is responsible for HOLDING the ELECTRONS within the SHELLS surrounding the ATOMIC NUCLEUS. It attracts the NEGATIVELY charged electronstowards the POSITIVELY charged nucleus. The particle that MEDIATES the force is the PHOTON - the lovely particle that is MASSLESS (it weighs NOTHING) and gives us LIGHT. PHOTONS can be absorbed and emitted by electrons. The range of the ELCTROMAGNETIC FORCE is INFINITE! Yes,there is no limit as to which this force can work.This is down to the MASSLESS of the photon. Example: a photon can leave the Sun and travel 93 million miles to Earth and be absorbed by you then re-emitted by you and absorbed by an atom of the wall of your living-room.

I could say lots of other things about the electromagnetic force! It's what holds atoms together into molecules or crystals. It holds molecules together into cells, and holds cells together into people or plants or pasta. It keeps two solid objects, such as you and the chair you're sitting on, from passing through each other, and so on!


THE WEAK NUCLEAR FORCE:

To be continued later today!

The Electromagnetic spectrum!!!

I'm proper looking forward to blogging about this!!!!!!! How Yorkshire am I!!!

Here's a quick fact:

Human beings can see only wavelengths between 400-700 nm.

A nm is a nanometre and in length it's interpreted as one-billionth of a metre.

700nm - red light.
400nm - blue light.

Stay tuned, I've got work this morning.

Comets and Asteroids

Differences;

Comets are made of water-ice - hence the tail that forms (this is like a mini cloud) and always points away from the Sun because it's the Suns heat that generates the tail - its cooking the comet.

Asteroids are made of rock - in my opinion, all the rocky planets are all massive asteroids that coalesced (accredted) into planets. The Asteroid belt is fundamentally a "failed planet" - it didn't all coalesce, probably due to Jupiters HUGE gravitational pull stopping it happening.

Comets brought all the water that you see to earth, they are made of water and the continuous heating from the planet - yes it used to be hot millions of years ago - and the Sun - melted the comets - giving us water - which is sutained by our atmosphere.

I will delve into the separate classes to make you aware of the variety of these space-dwelling beauties.

To be continued...........

Newton's laws of motion

You will have heard these before in School no doubt, here they are.

1. An object in motion will stay in motion, an object will likewise remain at rest (still) unless acted upon by an unbalanced force.

2. The greater the mass of an object the more energy needed/required to move the object in a given direction.

3. For every action, there is an equal and opposite reaction.

So here are explanations of the laws using scenarios.

1. If you let go of something that is moving, such as a shopping trolley (or anything with wheels), it will keep moving in a given direction before it hits something or looses momentum. This law is all about INERTIA. Inertia is the ability to resist change, as in practically every object around you has INERTIA, moving or not. A way for me to describe INERTIA is if you were in a moving car with your seat-belt on and the car suddenly stopped, you would move slightly forward. You do this because you HAVE INERTIA, which has effectively being given by the moving car. The seat-belt saves you and halts your momentum. FRICTION generally halts the movement of everyday things I.E it stops the car mentioned (BRAKES).

2. It's much easier to make something lightweight move than something super-heavy. Sound obvious?? Think of a bicycle and a lorry or a car. "Acceleration" means speeding up and that's what happens if you push something in a direction or drive/ride a vehicle. The harder you push or the more you put your foot down, the greater the acceleration. The less weight (bicycle) will accelerate quicker and easier. In physics, acceleration means ANY CHANGE from being still to moving, whether your getting up of the settee or running 100m. So if you are driving a car and you brake to slow down, the force of FRICTION gives you NEGATIVE ACCELERATION (you decelerate).

3. When a rocket pushes burninggas out of its engine, the gas pushes back on the rocket and lifts it into space. Forces can also be labelled as "actions" and always work in pairs. If one object pushes another then that object pushes back with the same force - the forces are equal. The effects may not be however as if you were to throw a tennis ball, the ball pushes back on your hand but the ball can travel a good distance. If you push down on the ground with your feet and the ground pushes back and flings you up into the air - you jump. The force from your feet also moves Earth! but not enough to notice!!

Kepler's laws of planetary motion

There are 3 laws:

1. Every planet orbits around the Sun in an elliptical orbit.
2. This concerns the speed of a planet around its orbit, and notes that an imaginary line between the planet and the Sun would sweep out the same area in the same given area.
3. The square of the time a planet takes to go round its orbit is proportional to the cube of the orbits semi-major axis (half the diameter of the planet's orbit).

The first law is relatively easy to convey, we all know that planets orbit the Sun and they effectively "circulate" it, better known as an orbit!!
What is important to understand is that a planet I.E Earth, has 2 key points in its orbit, these are known as the Aphelion and Perihelion.

Aphelion: Furthest from the Sun.

Perihelion: Closest to the Sun.

This effectively means that our orbit is not perfectly spherical and you're probably wondering why do we have these 2 key points??

Gravity pulls things together and in actual fact it wants to combine the Earth and the Sun and if it could it would, but it can't. Why?

The Earth is travelling at too high a velocity (velocity=speed in a given direction).

You may have heard the word FALLING mentioned when people talk about gravity.

Here's a pic to show the orbit:







You can see the 2 key points clearly marked. The Earth is bound to this orbit because of the gravitational pull of our Sun. The word FALLING may be easier to understand if I rotated the pic with the aphelion at the top, I'm not doing that as it would be illogical.

The Earth is travelling at a velocity around the sun which stops it being drawn in, however the gravitational pull of the Sun, results in this orbit. So the Aphelion is the point that Earth gets to when the Sun says "you're going nowhere" and pulls it back. The Perihelion is the point at which the Earth says "you can't have me".

A point to mention here is that the Earths velocity increases the closer it gets to the Sun - that is it is FALLING and everything increases its velocity as it falls. This doesn't mean it spins faster, it means it moves through space at a higher velocity.

You can see from the pic that our Moon has an elliptical orbit too!

Perigee: nearest

Apogee: furthest

Thats the first law.

Here's the second:





Sometimes labelled the law of "equal areas", the main principle to note here is that a planet will be travelling at its fastest when it's closer to the Sun and at it's slowest when it is furthest from the Sun. However, if I was somehow able to draw an imaginary line from the centre of Earth to the centre of the Sun, the line would be equal length at equal times.

Have a look at this picture:





You can see that although the triangles' sides are different, the actual area of each is the same. Please note that there are 12 Earths shown to reflect our 12 calendar months respectively.
The last part to note about the second law is that the short base of the triangles are a reflection that Earth is travelling slower (its further away from the Sun!). Therefore the longer base of the other triangles is a reflection that the Earth is travelling faster (it has travelled further over the course of the month).


Third law!

This is all about comparing the orbits of each planet in our solar system.

Probably a good idea to put this here:










AND THIS:

 

The important factor to establish here is that the closer the planet is to the Sun in general - I.E Mercury is the nearest planet, the faster/quicker its orbit of the Sun. This may seem obvious because it has the shortest distance to travel when compared to the other 7 planets. However, the time taken to orbit the Sun is due to the Sun itself, remember the point that the closer a planet gets to the sun, the more it accelerates. Well, Mercury is accelerating faster than all the other planets because it's the closest.

Here's an everyday example: you have an ice-skater on a rink who is spinning round and round with her arms out in front of her. In order to increase the speed of her spin, she PULLS her arms inwards to her body, the closer together she is - the faster she'll spin.

Planet	Period (s)	Average Dist. (m)	T2/R3 (s2/m3)
Earth	3.156 x 107 s	1.4957 x 1011	2.977 x 10-19
Mars	5.93 x 107 s	2.278 x 1011	2.975 x 10-19

You may wonder why I've put this table here, well it's because mathematics is an important part of the third law. I shan't go too in-depth. The main point is that:

The comparison being made is that the ratio of the squares of the periods to the cubes of their average distances from the sun is the same for every one of the planets.

Planet	Period (yr)	Ave. Dist. (au)	T2/R3 (yr2/au3)
Mercury	0.241	0.39	0.98
Venus	.615	0.72	1.01
Earth	1.00	1.00	1.00
Mars	1.88	1.52	1.01
Jupiter	11.8	5.20	0.99
Saturn	29.5	9.54	1.00
Uranus	84.0	19.18	1.00
Neptune	165	30.06	1.00
Pluto	248	39.44	1.00

The last column is the most important here. You can see that amazingly, each planet has the same T²/R^3.


No matter how long their "year" (orbit) is or how far away they are from the Sun. Kepler was able to devise a calculation that showed that every planets' orbit is the same.

The third law is also known as the LAW OF HARMONIES because every planet is in harmony with each other.

I hope you've enjoyed reading.

Much love, Adam XX.