“Will the world ever end?” asks Caroline (10)

Caroline. let us look at the possibilities that the team have suggested.

Yes we are destroying our world. Climate change will in the next hundreds of years will  probably make the Earth unlivable for humans. There might be some animals that will survive so life will survive even if we do not.

There are other things that could destroy our world. An asteroid strike killed the dinosaurs and if there is another strike it could kill humanity. It is reckoned that the Sun is about midway through it’s life. It will at some time begin to die BUT this will not happen for billions of years. When it does die the Earth (our planet) will also die.

Ronan (10) asks “How do stars form?”

Ronan ..this is my thinking about your excellent question.

Yes it is all about Gravity – There was a previous question by Tegan on Gravity. Have a look at it.

It is thought (it is therefore a hypothesis – an unproven idea)  that dust and hydrogen gas from the ‘Big Bang’ was gravitationally attracted to each other.

As the mass of the dust and gas got bigger it’s gravitational pull got bigger and the more dust and gas it attracted.

Eventually  the compact squashed ball of dust and gas started to heat up. It got hotter as it got bigger and eventually the particles of dust and gas began to break up in this hot environment and the hydrogen particles began to come together to make new particles … an atomic FUSION reaction began to occur and the star was born.

What does a dead star turn into? asks Liam (9)

Liam. Science is an interesting area of knowledge. It is recognised that it originates from an area of study called Philosophy. Philosophy (an Ancient Greek term) is about asking questions and for Science it is about asking questions about the physical and biological world. We ask the question and try to find the answers. For your question the answers are not easily found.

To try to answer your question, we have to know a little bit about the Sun. We know that in it’s centre there is an atomic reaction going on. It is not the type of atomic reaction we have in our Atomic Power Stations where we have an atomic ‘fission’ reaction occuring.

‘Fission’ means splitting something into two or more parts. The animation below shows a small atomic particle called a ‘neutron’  hitting a much bigger particle called an ‘atom’ . It splits forming more neutrons that hit other atoms, which break and form more neutrons………and on and on. This is a fission reaction and a lot of energy is released.

In the Sun the opposite is happening. Instead of fission we have fusion , the joining up of particles (Hydrogen atoms) to give Helium which creates lots and lots of energy. See the diagram below.

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Why would the Sun die? The main reason is that it runs out of Hydrogen. So what will happen then?  Firstly the Sun will get brighter. This will happen because of the helium that is produced. It will be pulled into the centre and begin to burn, adding more light and heat to the Sun’s radiation. Then as the hydrogen gets less and less the Sun will get cooler but at the same time begin to expand. It will become a Red Giant.

It is reckoned that it will expand so much that it will consume the Earth……that will happen in about 4 billion years time, however life on Earth will no longer exist in 1 billion years. This is because of the brightening of the Sun and the rising temperature of The Earth’s atmosphere, all the oceans will disappear and plant life will not be able to survive.

 

 

 

Yet more questions on Space and the Solar System from William, Kylan, German, Rob, Aidan, Gavin, Lucas, Jake, Thomas and Kylie.

Hello, yet more interesting questions. Many thanks. It is brilliant that you continue to ask questions. By doing so you maybe think that you are showing your ignorance, and you are. However it is important that you do show your ignorance because that is the way that knowledge and science develop. Scientists are constantly saying “I do not know how that happens” then “I will try to find out why it happens”. My answers to your excellent questions below might therefore not be direct answers but may be directed to helping you to find the answer yourself. You can be the scientist. Here we go …..

William asked “How many stars are there in space not including the Sun and what is the hottest planet in the solar system?”

William, the difficulty I have with this question is what do you mean by Space? Space is endless so for an investigation it is better to start with a smaller known area …such as our Galaxy, the Milky Way. Even then the answer is only an estimate ….about 1000,000,000 (a billion stars) and apparently it has been estimated that there are over 1000,000,000 Galaxies in Space.

Maybe the second part of your question has an easier route to an answer. Initially one might have thought that Mercury would have been hottest – it is the closest planet to the Sun! But I am wrong, Venus is the hottest, because of its atmosphere. Why do you think this is?

Kylan asked “Is Space endless?”

Kylan, the answer to this is YES. To us humans this must be a difficult thing to grasp. We are constantly living within confined areas. To think of something as endless is difficult to comprehend.
Kylan, a great but disturbing question.

German asked “Como se origino el universo?”

German, another difficult question. You are obviously in a group who specialise in asking difficult questions. That is brilliant, because that is what science is about, asking difficult questions. There is evidence that the Universe began some 14.8 billion years ago, the Big Bang. This evidence apparently comes from a something called CMB (Cosmic Microwave Background). I think I will leave it there. I have no doubt that the Big Bang idea will at sometime in the future be challenged. Another thing about science is that scientists are always trying to falsify other scientist’s theories (prove them wrong).

Rob asked “Why no one can go to the Mars?”

We will get there Rob. When I was at the Kennedy Space Centre there was a lot of talk about the proposed trip to Mars. They are even now investigating how astronauts can live in a small self contained environment for a number of years. We have got to the Moon, which is 384,000 km away, for Mars we will have to a travel a minimum distance of 54,600,000 km. Why do I say ‘minimum’ distance for the Mars trip and not the same for the Moon trip?

I think it may happen in your lifetime.

Aidan asks “Why doesn’t NASA use a Saturn V rocket to go to Mars?”

They have a Saturn V rocket at the Kennedy Space Centre. It is massive. However they will need a more powerful (notice I don’t say bigger) rocket to launch a Mars probe which includes astronauts. The living module will have to be a good deal bigger than that used to get to the Moon and back.What do you think will be necessary for the astronauts survival?

An image of the engines of the Saturn 5 rocket  at the Kennedy Space Centre

 

Gavin asked “How does the Solar System work?”

Gavin, great question. I have already answered a similar question in a previous post. This was my answer to Rishi:

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?

Lucas asks “How big is our solar system and do humans know if there are other solar systems?”

Lucas, NASA has a project called Keppler that is looking at other planetary systems. Below is an image of the space telescope that is doing this work. Note that our planetary system is the only one called the Solar System. All others are called planetary systems. The Kepler telescope has identified a number of other planetary systems and some of them are very strange. One system has two stars. Quite a few have Earth like planets. I wonder what it would be like living on a planet with two stars?

Jake asks “Will Mercury crash into the Sun in a million years?”

Jake, it is unlikely that Mercury will crash into the Sun. It is thought that as the Sun gets older, it is now about 4 million years old, it will begin to expand  and eventually destroy Mercury and Venus and the Earth. It is reckoned that this is likely to occur in 4.5 million years time.

Thomas asks “How does the Sun create radiation?”

Thomas, how many types of radiation do you know about? There is visible light radiation,  ultraviolet light radiation, and infrared radiation.  However, there is another type of radiation which produces all of these types of radiation.

The Sun’s radiation is created by a nuclear fusion reaction in its core. This nuclear reaction produces very high energy gamma radiation which, as it passes from the inside of the Sun to the outside, is converted to the other types of radiation listed above.

Kylie asks “Why does Saturn have rings?”

Great question Kylie. Saturn is one of the largest planets in our Solar System. It therefore has a great gravitational attractive force. It has 60 Moons! It is thought that the rings have been created by this gravitational force attracting lots of the bits and pieces that each year enter our Solar System. Bits and pieces like asteroids and meteorites. Gravity is an important feature of our Solar System. Have you any questions about Gravity? I would like to hear them.

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.

Caroline (10) asks “Will the world ever end?”

Thanks team. It is thought that in 4.5 billion years time the dying Sun, then a Red Dwarf will expand as it runs out of energy. The expansion will reach our worlds orbit so the planet Earth will be destroyed.

Obviously before then the Earth might be hit by asteroids or some other catastrophic event so although the planet might survive, life upon it might be destroyed.

Below is a short animation of the Sun’s expansion at the end of it’s life.

 

 

 

 

 

 

 

Could the Earth’s core be hotter than the Sun? asks Brooke (9)

Brooke. When earthquakes occur ( For how they occur see this question) you get a seismic wave travelling outwards from where it occurred. Imagine an explosion, a rock cracking a noise bigger than anything  you have experienced.  It would create the biggest sound ever, shake the ground more than it has ever been shaken and send a signal to the rest of the Earth that the earthquake had happened. It is this seismic wave of spreading energy that has helped scientists discover the structure of the inner Earth. The waves spreads out in all directions and some of them pass through the centre of the Earth. If you look at the waves on the other side of the Earth you can examine them and find out what they have travelled through.

It is now thought that the temperature of the inner core is close to 7000 degrees K (Kelvin). It is however not a liquid , because of the pressure of all the stuff on top of it. It is therefore a solid iron core at about 7000 degrees K…which is close to the outer temperature of the Sun.

(0 degrees K=273 degrees Centigrade so 100 degrees Centigrade = 373 degrees K )

“What is the Earth orbit speed?” asks Joselo (12)

Joselo I would be interested in why you asked this question.

It is about 108,000 km/h. That is very, very fast,  Think of a fast car..it would be going at about 100km/h. The orbit around the Sun takes 365 days and the distance travelled is 970 million kilometers. Quite big figures.

I would be interested to know why I don’t feel that I am travelling at such a speed?  Why doesn’t the Earth lose its atmosphere?

Feel free to ask another question.

Mary Ann (10) asks “Why are most leaves on trees green?”

Mary Ann. I sometimes think it is amazing that  leaves are so successful because they reflect green light ….the don’t want it.

Remember that white light from the Sun is a mixture of all different colours.Below you can see the result of white light being passed through a prism. the chlorophyll in leaf absorbs the deep blue and the red light and reflects the green light.

For red leaves the chlorophyll is hiding in the colour of the leaf. Our eyes cannot see it.
If you want to know a little bit more then ask another question.

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