Some Questions about the Solar System by Rishi, Ned, Maya, Thomas, Jackson, Adam and Pug.

Many thanks for the questions, and they are all about the Solar System. Amazingly I have just (three days ago) visited the Kennedy Space Centre in Orlando so they come at a time when I am excited by the science associated with space and space travel. I had questions before my visit and after it I had more. That’s the brilliance of these exhibitions, they raise questions. So let’s look at yours.

Rishi asked “How does the solar system work?”

I immediately think of why does it work in the way it does? The centre of the Solar System is the Sun. The Sun is one of a group of stellar objects called stars. Our star was named, by somebody, in the past, as the Sun.  Our star (the Sun) seemed to have attracted to it some massive lumps of matter/material which we call planets (planets are the biggest ‘lumps’ , the smaller ‘lumps’ are called asteroids and meteorites. What has given the Sun the ability to attract these ‘lumps’?

You then have the amazing thing that these lumps move around the Sun. They are attracted to the Sun but do not fall into it. They rotate around it, why do they do that? . Or does the Sun rotate around them?

So Rishi, your question is a great science question. From it lot’s of other questions arise, and that is what science is really about.

Ned asked “If the world split in half, would there still be a gravitational pull?”

Ned, thanks for the question. Gravity is one of those strange things called ‘forces’. Most forces are easy to define. You push things, you pull things by physically applying a force. Magnets  can push and pull so they can apply a force. So how can you explain the fact that things are somehow ‘pulled ‘ towards the Earth?  This seems to be something called a gravitational force. It’s strange. Nothing seems to be pulling or pushing you. Scientists have created a word called ‘gravity’ which describes the process of one object (of a big mass) pulling towards it a smaller mass.

We know that there is this force called gravity that exists. I am not sure that we have yet found out what causes it. We know that a very big object (of great mass) will attract a much smaller object (of smaller mass), however we have no idea why.

So at last to your question. My hypothesis (find out what that means). Slitting the world in half would mean that both halves of the Earth would move closer to the Sun because, the Sun is the biggest object in our Solar System.

Maya asked “What is the milky way?”

Maya, it’s a good question. I wonder who first used the name ‘the milky way’ and why? I firstly think about stars in the night sky, they produce white light (I wonder why – why not red or yellow light?). Does our star (the Sun) produce white or yellow light?

It is for a lot of us to really observe the night sky in all its glory. Why? It seems to be all the background light that we are experiencing when we look at the night sky. Go to a very dark place, away from the city, away from a near town and look at the night sky. You will see things you have never seen before. It is magical. You will see more stars than you have ever seen in your life. Only then will you see the Milky Way and only then will you know what it means.

Thomas asked “How many Suns are there in the universe”?

Thomas, thanks for the question. My first question is . What do you mean as Universe? As yet the investigation of the Universe in which we live is incomplete. We do not know how big it is. We do know, that the Universe consists of groups of stars that we have called Galaxies. We are in a Galaxy called the Milky Way (see Maya’s question). There are millions of stars in our Galaxy. So Thomas, in answer to your question ….we do not know …but the important thing is that you asked the question. By asking the question the quest and research for an answer continues. That is science.

Jackson asked “How big is Jupiter?

Jackson, a great question. It raised a question which I tried to find the answer to “Why do we want to know the size of Jupiter?’ I suspect it is to try to answer an even bigger question linked to Risha’s question. Why do the planets orbit the Sun? Is there some reason in there order of orbit …Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune?   Jupiter is the biggest planet in terms of mass and size in our Solar System . It would be nice if the size and mass of the planets and their orbital position was a straightforward order …but not so. That seems to be the outline of another question.

Adam asked  “How old is the Sun”

Adam, an interesting question, thanks.  It is thought that the Sun is 4.6 billion years old that is …would you believe it 4,600,000,000 years. Scientists reckon it was formed by the sudden compression of hydrogen and helium gas caused by the explosion of nearby star. Wow. This leads to lots of other questions …..think about them and let me know. The scientists also reckon that the Sun is about halfway through it’s life.

Pug asked “If all planets crashed into each other would it affect other Solar Systems?”

Pug, a good question. What do you think would happen if all the planets crashed into each other? How would it happen? Here is ia hypothesis. The most likely scenario would be the outer planets moving into a lower orbit and crashing into the lower orbit planets. They would then be affected by the gravitational pull of the Sun. They might then crash into the Sun. The Sun may therefore gain more energy and explode into a supernova. Pug, a hypothesis is an idea, can you come up with an alternative one? Let me know.

“How does a magnet become a magnet?” asks Ava (11)

A brilliant question Ava. I asked my team for their thoughts.

Yes team you are quite right there are some limitations to magnet making. The main one is that only certain metals can be made into magnets. These metals are called ferromagnetic metals.

Included in this group are the metal iron and the alloys of iron with the metals cobalt, nickel and some other rare earth elements .

It is thought that in these metals (including iron) have some electrons called ‘free electrons’ (not sure what an electron is, then go to Science Master Special – Atoms and Atomic Structure). It is these ‘free electrons’ that are involved in magnetism. In the alloys the  ‘free’ electrons align themselves with the magnetism of the external magnet, making a (for the alloys) a permanent magnet. For iron alone the magnetism is only temporary and you can test this in the experiment below.


Look at the short video I have made below. In the ferromagnetic metal (iron alloy) crystal domains you will see free electrons. In the metal these will be moving freely. As they begin to interact with the external magnetic field, they begin to align themselves, making a permanent magnet.












Keith (13) asked a question about thermal papers in cash machines.

Keith’s question
More and more places are using thermal paper as a form of receipt paper for customers. With time the information fades. How can one scientifically go about recovering information which may have faded from thermal paper.

Keith, many thanks for the question. I never realised that thermal(heat sensitive) paper was used in so many places and that it is also the basis on which the polaroid camera worked.

Thermal paper is made using a collection of dyes which exist as colourless crystals that become coloured when they interact with an acid.

For those who enjoy their chemistry you might have come across adding a dye called phenolphthalein to an acid solution. The dye changes from colourless to a deep purple.

The applied heat (from the cash register machine) melts a layer in the paper which contains acid crystals. The liquid acid then interacts with the layer below it which contains a colourless crystalline dye which changes colour as the acid interacts with it.  The print then shows. The acid quickly becomes crystalline again.

Over time the print does begin to disappear.

A little investigation.

Obtain an old till receipt which your adults do not want to save. Put it onto an ironing board and with a hot (care) iron, iron it.


To make it more scientific predict what you think might happen before you carry out the experiment. Any ideas, if so you have a hypothesis.  Now find a very old (fading) receipt and using a hair drier blow warm air onto the BACK of the receipt. Again predict.

I think I’ll stop there. Many thanks for the question Keith. Please comment or ask another question.

Braiden (9) asks “What makes a diamond so hard?.

Braiden, my question (before I turn you over to my team) is how do you detect ‘hardness’? Can you create an order of hardness with some common materials?
Lets say:

wood (balsa)
wood (oak)
plastic object
bath sponge
china(cups and saucers)
concrete pathway
metal fork
rock (sandstone)
piece of coal
pencil rubber 
For obvious reasons I have not included diamond in this list. I think that would be an interesting experiment to carry out. You will have to make sure it is a fair test 

Now over to my team.

Graphite has a layered structure with weak forces between the layers, This is a weaker structure than the close bonding of the diamond. The carbon atoms like the tetrahedral arrangement of the bonds with other carbon atoms. It is a very strong force.

Hope that makes some sense. If you have questions about the explanation please ask them. If you want to see my ‘hardness’ list go to Science Master Special-Hardness Results

Updated 15/1/2018  Experiment added.

“How did evolution happen?” asks Parm (10)


Parm, it’s all due to some wonderful stuff called DNA however the beginning of life is at the moment attributed to  a simpler chemical called RNA. Somehow 4.5 billion years ago, in a hot chemical quagmire a collection of complex chemical structure was formed which was living, it could reproduce itself. It is thought that this microscopic entity was quite close to the structure of present day bacterias although, it’s make up was completely different. For example it didn’t breathe Oxygen, it is thought that it might have breathed a chemical called Ammonia and it expelled Oxygen. It also, in its structure contained a crude DNA structure.

From this humble beginning all life on Earth evolved dictated by changes in the  DNA molecules that were part of their structure. Plants, Insects, Bacteria, Animals, Fungi, Algae,  all life contains their own DNA molecules which dictate their continued existence.

So for Jeremey, our snail there has been, for some reason, a small change in her/his DNA. The spiral is wrong. Maybe it might be wrong but it might help Jeremy eat a plant that he/she couldn’t eat before and therefore survive and breed more snails like him/her.

Over the millions of years that life has existed on our Earth, now and then, new life , created by old life, experiences a slight change in the DNA, and that means that the new life is slightly different from the life of its parents (plants, animals, fungi ….). If the new life survives, that life will create more new life in it’s form, evolution has taken place.

Hope this makes sense Parm. Any thoughts? Write them in the ‘Leave a Reply’ box.

“When the Sun blows up will Mercury smash into Earth?” asks Flynn and Freddie (10)


Below is a short video of the expansion of the Sun. Again this is a hypothesis based upon observations of our Universe.

The expansion is thought to be caused by firstly the Sun running out of fuel (it uses  Hydrogen, converting it by a fusion reaction to Helium). As the Sun cools the centre will expand, (any thoughts on what might cause this?) pushing out the rim of the Sun and consuming Mercury, Venus and The Earth and eventually it becomes a Red Dwarf. It is suggested that Mars will survive.

What is the difference between a hypothesis and a theory?

Hope this helped. Please comment or ask another question.
(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

A question “How does the world work”

Some time ago a well known scientist (James Lovelock) suggested that the Earth (our planet) was special. He claimed that the Earth itself was a living thing and had control over its environment. He gave the Earth the name Gaia (a Greek name for the goddess of the Earth) and suggested that the planet’s objective was to support life on it, at all cost.

It has been argued, by those who support this idea, that there is a lot of evidence from investigating the Earth’s history over the last 3 billion years, that suggest the idea is valid. Below are some of those arguments. What do you think?

The Gaia idea is something called an hypothesis (an idea). It has yet to be proven. If proven it can then be called a theory.