Mitchell (10) asked ‘What would happen if the Earth stopped spinning’

stopspin-copy

A great question Mitchell. Can you think of any other thing that might happen?

Firstly the speed at which the spin happens is measured at the equator. Any idea at what the speed would be at the North and south poles? If the Earth suddenly stopped spinning what would be the effect at the poles?

How long will each day and night be? Remember although it is not spinning it would still be orbiting the Sun.

Interestingly, because of the Earth’s spin the Earth has a bulge around its equator.  Remove the spin and the Earth will become a true sphere. This will however cause a redistribution of the Earth’s oceans. The world after the spin will look a little bit like it is depicted in the video below, a big continent in the equatorial area with an ocean either side of it.

Another thing that will happen is that the Earth will lose it’s magnetic field. No longer will you be able to hold a compass and see the pointer pointing to the north pole.

Sheereen asks – “Where do the items that a black hole suck up, go to?”

Sheereen, I was always told that a Black Hole was a place where my money or lost items apparently disappeared without trace. But I think your question deserves a different answer. I asked my friends about it. I shall also ask them to avoid science fiction stories where Black Holes seem to be used in a variety of stories. Do Black Holes really exist I might ask?

blackhole

My friends are right. The denser (more compact) the mass (think about mass and weight) of an object the greater its gravitational pull. So when the Sun collapses into itself you have a object that gets very small and very, very dense so it’s gravitational pull increases and it begins to pull everything in towards it. when something is pulled into it (including light) where it goes to is a mystery. It may add to the mass of the collapsed Sun and make a stronger black hole by increasing the gravitational pull. OR as the Science Fiction writers would suggest it takes you to a new dimension. Thank you for your question Sheereen.

Walter Jr. (Grade 2) asks “I’ve heard the Sun revolves around the Earth, but I’ve also heard that the Earth revolves around the Sun. Which one really happens and how do we know?”

change-mind

My turn now. The astronomers at that time had noticed some strange behaviour when they were looking at the planets. For example, when they looked closely ( over many days) at the the path that Mars was taking in the night sky they were surprised to find that it suddenly started going backwards for a short time before continuing on a forward path. It did what astronomers call a ‘retrograde loop’ .  This could not be explained by a model where the Earth was the centre of the Universe with everything orbiting around it. It could however be explained if the Sun was the centre of our small universe(Solar System) and the Earth and the rest of the planets orbited it. The retrograde loop observation is then explained by the different orbits that each planet makes around the Sun. See an example in this link.

Ernie(13) asks -“What is at the centre of a black hole? What would happen if you fell into one?”

black-holes

We obviously know something about gravity. We know that it is a force that is generated by the mass of an object. The bigger the mass the bigger the force that it exerts on other objects. So we feel the force of Earth’s gravity on us and the Earth feels the force of the  Sun’s gravity on it. The Sun’s gravitational force keeps the Earth on an orbit around it. If it didn’t exist the Earth and all the other planets would start wandering in space.

Black holes are thought to be a source of a massive gravitational force, because of their mass , which is constantly increasing, and they don’t just pull other matter to them they pull light in as well …thus a black hole. No light – darkness.

So to your question.  I think you could now answer that yourself.

“Can u jump off the world into space” was Austins question.

A great question Austin however I think you are going to be a little bit disappointed by my friends answers.

falling to earth

What a way to hand over to me!

To think about gravity you have to think about the really big things. the gravity of the Earth pulls on the Moon and keeps it in orbit. The gravity of the Moon pulls on the Earth and causes the tides. So gravity doesn’t end when you leave the Earth. Austin, jump and you will fall a long, long way.

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Those astronauts are falling all the time but because they are moving around the Earth the ground is constantly moving away from them. If there spaceship stopped moving around the Earth it will fall and hit the ground. (revised 10/09/16 -miscalculation 13/09/16 new animated gif)

Lake’sha (8) asked “If there’s a new moon every month. Where does the old one go?”

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I feel that the answers my friends have given do not really answer your question.

Your question is about the new Moon and why is it always new?

My question is, is it new? When you see the Moon, with the Sun shining on it look at it’s features. Record in some way what you see. Make a drawing, take a photo. Look at it the following night and see whether more features have been added. Record them. Observation and recording are important features of science investigations. You have a fabulous question which you can answer.

Unsure than ask a question.

Do the above and then read the below.

The Moon is a difficult object to follow. One month it appears every night in the night sky and the next month  … no sign of it.  Now and again you might see it in the sky during the day! it is a very, very confusing ‘animal’. This is because it orbits the Earth every 28 days so for some time each month those who live in the southern part of our planet can see the moon while in those in the northern part see it in the other part of the month.

Jessica (8) asks – How do the planets orbit the Sun? How many moons does Mars have?

Jessica. A great question. You also asked a question about the Moons of Mars so I will try to answer them both here. Firstly I asked my friends about the orbits of the planets.

orbits
Sometimes I think they tackle the easy bits and give me the hard bits.

Lets look at what we mean by a force. A force is a push or pull on something that you are interacting with. You are applying a force on somebody when you push them away or you are applying a force on something when you pull them to you. When you let go of them the force ends. When you are throwing a ball you are only applying a force in the throwing process. When you let go of the ball the force that you were applying ends.

Simple, but

Some of the forces can be applied without touching the thing you are forcing. Magnetism is an example one magnet will apply a force to another magnet without touching and  Newton realised that when objects fall towards the ground they fall because the Earth is applying a force on those objects. He called that force Gravity.

Now what is happening to the planets. Here is a little experiment. Tie a ball to a piece of string (a polystyrene ball would be the best). Now holding the end of the string spin the ball around your head (probably best to do this in the garden). Can you feel the tug(force) being applied on your hand. Now let it go. What happens? Does it just drop to the ground. Now think about this. The ball is a planet and your hand is the Sun. Not only gravity but another force linked to the speed of the flying ball and it’s mass is in action. Maybe it is the application of these two forces that make planets orbit the Sun?

Sorry long answer. Please comment if you want to by going to the Leave a Reply Button ….guidelines are available.

Mars has two small moons Phobos and Deimos.

A video that may help –

Ruby (8) asks “How does the Sun heat the Earth”

Ruby, I thought I would ask my friends about this question.

sun's heat

My friends were not as helpful as they usually are. More questions for me. Let’s look at ‘energy’ first. An explanation I like is – Something has energy when it has the capability of doing something to something else.

Heat is a form of energy because it has the ability to make things warmer. Light is a form of energy because it helps us see things by reflecting off them. Maybe you could continue this list. I think there are about 8 different forms of energy.

One of them is radiant energy. The energy made by the Sun is radiant energy. Radiate means to spread out from a point – this is what happens to the energy of the Sun. This radiant energy has the special ability of being able to travel through a vacuum and as the Space between the Sun and the Earth is a vacuum the Sun’s radiant energy can reach the Earth. Some of that radiant energy is light energy other bits of it become heat energy which on some Summer days keeps us nice and warm.

Ruby. It was a good question. I have tried to reply to it as best as I can. If there are further questions go to Ask Another Question or leave a reply in the Leave a Reply box below … you do not need an email address.(revised 20/7/16)