why is panet earth unique?

Answer 1

First, the composition of gases, element is crucial for life-making. We have suitable element like silicon to create earth crust to reduce heat convection of earth's core.

Secondly, early earth is strucked by moon, the moon cause earth to rotate anticlockwise, the speed of the collision, the mass of the moon, the position of the moon striking, the angle of the moon striking, 23.5' is so so so so perfect.

Thirdly, earth is protected by moon from collision. Earth's distant big brothers, Jupiter & Saturn are continuingly sucking meteorites and asteroids from travelling towards the earth.

Fourthly, the distance between earth and sun is so perfect. Too near is too hot, too far is freezing cold for chemical reaction to take place.

Fifthly, earth's core is constantly rotating, producing the magnetic shield from harmful radiation from the sun.

The list goes on.

Answer 2

Because the earth's orbit and properties are in many of what astronomers call a "Goldilocks Zone". For example:

The moon is about 1/3 the size of the earth and orbits the earth causing tidal action so the oceans don't become stagnant. It shields us from many incoming meteors, it helps to correct the orbit of the earth as it goes around the sun and keep it's spin on its axis stable.

The earth is the optimal distance from the sun required to sustain life. Much further away and it would be too cold to really support life, and much nearer it would be too hot to support life. It's got Jupiter in an appropriate orbital distance to help to stabilize the orbit even further. Jupiter and the gas giants also serve as an additional meteor shield for the earth since they're so much more massive than earth they're more likely to pull an incoming meteor into their orbit therefore allowing the earth to be relatively unharmed by any large meteors for the most part.

The orbit of the earth is a slight ellipse where as most other extra solar planets are exagerated ellipses and have very erratic orbits. The composition of the atmosphere is perfect for sustaining life.

The molten core provides a strong enough magnetic field to deflect most of the deadly radiation from the solar winds generated by our sun.

The ozone layer above the earth helps protect life on earth from much of the UV rays that come from space.

The sun is the right size to support life on earth, it's not a white star, or a massive red star.

These are just a few aspects that make the earth unique from any other planet in the solar system or perhaps even the galaxy. The odds of finding a planet that has as many "Goldilocks Zones" or even features is astronomically small.

Answer 3

Short, philosophical almost, answer: Planet earth is unique because human race is shortsighted, selfcentered and proud. One example, earth was believed to be at the center of the universe (so we wanted to be) when evidence proved the contrary (which didn't suit a few religious institutions).
Planet earth is also unique because human race is leaving in no other place and can't yet go anywhere else... so better not trash it to much...

Long answer: in its physical setting it cannot possibly be another. however, our galaxy is big and the universe (of unthinkable dimension and still growing) is full of galaxies. The probability to find a planet in all points similar to earth (even including life) is obviously not null . We have not find any but remember that the absence of proof is not proof of absence.
You may hear more and more these days the terms "life as we know it"... well it's because we can't eliminate the probability life may take different chemical aspects (no DNA, RNA, proteins, maybe silicon based, anything really...) and may originate in places very different from the one we would expect our life form to have developed. But we can't look for things we can't comprehend, we wouldn't recognise them most of the time (if any), hopefully by chance maybe one day we'll discover (utopically i'd have said imagine, but i guess we're already struggling understanding our own life form, how can we imagine something else) maybe not that far, maybe in our own solar system, who knows. Consequently, we are only trying to find earth-like planets (technically still quite difficult) to find what we can comprehend.

Answer 4

Unique:

1.) Earth is located just far enough from its star, the Sun, to provide moderate heating and not intense heating/radiation or minimal heating. Distance to star = 93,000,000 Miles.

2.) Earth is not a gas giant. It does have a solid mass, and what is more important, it has a metalic core which gives it a large gravity pull. That gravitational pull is large enough to retain the gases which form our atmosphere. Were the gravity less strong, those gases would escape off into space and there would be no air to breathe.

3.) Earth has a large supply of water in liquid form.

4.) The Earth's atmosphere blocks most of the harmful radiation from the Sun such as X Rays and Gamma Rays.
You can still get some rather painful burns from UV light on bright, cloudless days if you are not careful.

5.) The Earth is spinning at such a rate that most surfaces get equal opportunity for solar heating, and not many places are left frigid. Certain other planets spin slowly and it is a long time between Mid-day and Mid-day, causing temperatures to vary from quite hot to very, very cold.

One person who replied to your question indicated that we had been searching for 6 years and not located an earthlike planet yet. Not true... scientists and astronomers have discovered 239 other planets orbiting around distant stars so far in their search. One of those is fairly earthlike and orbiting a star 20 light years distant from us. It is four to five times the size of Earth and seems to have all of the necessary features to qualify it for the "earthlike" description. Much more study is required. The Milky Way contains some 200 Billion stars and each one of them could have from 0 to 10 planets with their associated moons orbiting around them. Thousands of other galaxies exist outside of our Milky Way Galaxy and each of those contain billions more stars. The same deal applies to each of those stars, regarding possible planets with their associated moons... So, there are many, many chances for the existance of a real mate for Earth.

Answer 5

It's a double entendre - planet Earth is unique in that it has just the right balance of ingredients to support abundant forms of life, but it's not unique in that there could probably be millions of planets in the known universe that have a similar, if not better environment to support life.

Its been established that the following ingredients are vital to support life *as we know it*:
- Water
- An atmosphere with breathable Oxygen, Nitrogen and other gases
- The right temperature

Earth is 70% water, an atmosphere with 70% inert Nitrogen, <30% oxygen and the rest as other gases and habitable temperatures of 10-50 degrees centigrade.

Earth is just the right distance from the sun (it's not too far to become too cold and not too close to become too hot) and has just the right size to support life (not too large to have too much gravity and not too small to have too little gravity like the moon).

All these factors make it unique *in our solar system* and probably nearby stars, but chances are there are many many planets out there with a similar environment.

Answer 6

Earth is only unique in the solar system.
Solar systems with earth like planets are dotted throughout the universe we may never detect their presence but they are there.

Answer 7

It almost certainly is not unique. There may be billions or maybe only millions of planets in the Universe which are very similar. We don't know because we have not seen far enough to know.

Answer 8

In all honesty, that is only to us, because we've never been on any other planet. But once we can go further into space, there is the highest posibility that we will find another planet like ours. Personaly, that day will be the best in all humans days.

Answer 9

We have found an astounding number of new planets in the past 6 years and still have not found one like our planet earth.

Answer 10

because we're the only planet where living organisms can survive. We have gravity. We have oxygen. We have everything we need to survive as a human. and no other planet have that.