Hello Heather and Keira,
Firstly, let me apologise for taking two weeks to reply to your question. It has been a very busy time working on a project for a choir but I now have two weeks before the next project starts so it's time to catch up.
I now have another post for you but it may be challenging to understand some of its content. I have found the more I learn, the more I realise how little I know. Checking ideas and information for you and others when I write a post can often challenge my understanding but its by challenging ourselves to understand we can learn.
Back on the "How did Earth begin?" post I tried to answer your challenge. Like all good enquiring minds, one idea can lead to another so, in the comments section, you added...
In one of the paragraphs, we noticed that you talked about possible life on Mars. Keira thinks that over time, the sun will come too close to Earth, and Earth might shatter. That might be a possibility. There is one problem though. Martians could have died, but Mars didn’t shatter. Do you think that WE are Martians CHANGED into human?
Our minds can be a very powerful weapon against ignorance when we have curiosity and a will to find answers. This is particularly important for science as it tries to find the answers to questions. As lovers of science, your curiosity can lead you in all sorts of directions. I know mine does as I try to find answers. Let's look at a simple answer...
Do you think that WE are Martians CHANGED into human?
Too quick an answer?
Let's put it this way, I'm not comfortable completely ruling out many ideas. It is possible first life on Earth came from Mars but I don't think it's likely.
Here's some mind blowing maths for you. Just say you shuffled a deck of playing cards and put four down on the table...
When you put down the first card, the chances of it being a 7 of Diamonds is 1 in 52 because there is only one 7 of Diamonds in a deck of 52 cards. To then put down a 3 of Clubs, the chances are 1 in 51 because there were 51 cards left. For the King of Spades, it's one in 50 and, for the 10 of hearts, 1 in 49. So what is the chance of dealing just those four cards in that order from any normal deck of cards...
The chance of dealing those exact cards in that order is only 1 in 6,497,400 ... (52 x 51 x 50 x 49 = 6,497,400). It's not very likely we would get those exact four cards in that order if we shuffled and dealt four cards again but it is possible. Of course, a magician or a card trickster could cheat to get the results over and over but then the cards aren't random.
This type of maths looks at probability, i.e. chances of something happening. If we only have one card and it's the King of Clubs, the chances of dealing a King of Clubs is one in one or 100%. The chances of dealing a 7 of Diamonds is zero in one or 0% because we don't have that card. Can't maths be amazing?
For really mind blowing maths, go to the end of this post where I work out the chances of dealing out all 52 cards in an exact order, at least if I have the maths correct.
Where Did Life On Earth Come From?
I know of two main ideas for the origin of life according to science.
1. The Primordial Soup
This idea suggests billions of years ago, chemicals became concentrated (thicker) in pools of water (the primordial soup). By chance, these chemicals were able to form amino acids (the basis of life including us). In time, they combined to make more complex compounds and eventually life. This process is known as abiogenesis.
The chances of life in this way would be seen as very unlikely but, if this process is correct, it did happen. Look again at the card example in "The REALLY Mind Blowing Maths" at the end of this post. The order of cards I dealt was very unlikely but it did happen.
Some theorists suggest life might have evolved elsewhere and was brought to Earth on meteorites (Panspermia). This might be better suited to the idea life on Earth started on Mars. If life had started on Mars, a meteor strike might have thrown Mars rock into space and it may have made it to Earth but, then again, life on Earth and Mars might have come from anywhere in space. Remember, if it was life, it would have been very simple, possibly single cells, not animals like us.
No, if you watch the video clip to the end, I don't believe aliens are experimenting with us. It is possible but very unlikely. 🙂
What does Ross think?
The first idea can explain how life itself could have started, whether here or somewhere else in the universe. The second suggests how life might have made it to many places in the universe. Think of it, life might have started in many places in the universe and been spread to the stars, or at least their planets.
Did Mars Once Have Oceans and Rivers?
One of the important resources for life as we know it is liquid water. There is evidence rivers, lakes and oceans once flowed on Mars but liquid water hasn't been seen on Mars. Much of the water was probably lost to space long ago. There is plenty of evidence water as ice is found at the Martian poles and growing evidence it is to be found in the rocks and soils so life may well exist there waiting to be discovered but don't expect anything like animals running around. It's very unlikely intelligent life ever existed on Mars but is likely life did and/or does exist.
You have questioning minds so I suspect you're wondering, what happened to the Martian oceans and rivers?
Here is a video looking at the way Mars may have lost much of its atmosphere...
You may have understood the idea energy from the sun (the solar wind) caused Mars to lose most of its atmosphere so you might wonder why this didn't happen here on Earth.
Why did Earth keep its thick atmosphere while Mars lost much of its atmosphere?
Let's first look at the photo I prepared for you. It's made by placing a magnet under a piece of paper then sprinkling iron sand over the paper.
The lines you can see in the sand help us see the magnetic field of the magnet. You can see the lines run from one end to the other of the magnet. The Earth also has a magnetic field because of its rotating iron core in its centre. The iron core helps create a much stronger magnetic field than on Mars. It protects us from much of the solar wind. Think it of a little like an umbrella in the rain.
Earth's umbrella (magnetic field) is stronger than that of Mars so we get better protection. Below is a NASA diagram showing the magnetic field of Earth. If Earth's centre cooled and slowed reducing our magnetic field or solar wind became stronger, Earth would also eventually lose much of its atmosphere.
Keira thinks that over time, the sun will come too close to Earth, and Earth might shatter. That might be a possibility. There is one problem though. Martians could have died, but Mars didn’t shatter.
Watch this video clip...
In this model of Earth's future, the Earth would eventually be pulled towards the sun and, in a sense, "shatter". Its matter would turn to plasma, a major part of the sun. I have shown Mars didn't lose much of its atmosphere because it shattered, it was lost because it didn't have a strong enough magnetic field to protect it in the way Earth is protected.
I found another video but it is harder for you to understand. It was made by a college student as an assignment looking at the life of the sun. At the stage where our sun becomes a red giant life would no longer be possible on Earth but we are looking billions of years into the future. In this model, it's not so much that the sun comes closer, it grows larger.