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)

“Why do stars twinkle” asked Mia (8)

Many thank team. I think Mia has all she needs for a little bit of experimentation.

Mia, in a darkened room , put the aluminum foil on the floor, place the bowl over it and shine the torch onto the bottom of the bowl.

What do you see?

Now add some water to the bowl(about half full). Let the water settle and then shine the torch onto the bottom of the bowl.

What do you see?

Finally, still shining the torch onto the bottom of the bowl give the water a bit of a vigorous stir with a spoon or even the end of a pencil.

What do you see?

Is what you see when the water is moving different from when it is not moving? Maybe the moving water is a bit like the moving air through which you are seeing the stars.

Tell us what you see. you can do this in the Reply box below.
(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

Liam (7) asks “What causes an earthquake?”

Thanks team. When the Earth cooled down the crust was formed over the whole planet.

However, after the crust was formed there was still a lot of activity in the molten core of the Earth. This caused cracks in the crust and it is these cracks which are the cause of Earthquakes. Scientists have investigated the cracks and created a map of where they are.

You can see these in the maps below.

The lines indicate the cracks on either side of our Earth. The spaces within these cracks are called¬† ‘plates’. These plates are constantly moving (very, very very slowly).

Any idea what is making them move?

Some plates are moving away from the plates next to them BUT that means they are also pushing up to other plates on the surface. It is this movement that causes the earthquake.

Where do you think the earthquake happens …is it in the middle or outside of a plate? Where is your country?

I have created two jigsaws of the Earth images above. Print them, stick them on some cardboard, and cut them out and make your own world of ‘plates’ and try moving them.

Link to Jigsaw 2

Link to Jigsaw 1

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

“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)

Angus and Lachie(10) ask “Are aliens real?”


……………..I personally think that with so many potential places where life, in what ever form could have developed that aliens do exist and we have now, to wait, for contact.

Of interest is that life started developing on Earth in a very different way from how we would expect. The early bacteria were, it is thought, cyanobacteria. This bacteria ‘eats’ Nitrogen gas and exhales Oxygen and in doing so killed itself by poisoning its atmosphere. The Earths atmosphere moved from being a Nitrogen to an Oxygen atmosphere. So ………………………..this might not always happen on other Earth’s thus the type of life which humanity may meet in the future could be Nitrogen based.

The cyanobacteria do still exist in Earth’s deep oceans.

Also look at a previous post on aliens.

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