what makes our planet alive ? i'm confused?

2015-11-11 2:07 pm
the sun ? the water? the air ? or the dark matter ?

回答 (16)

2015-11-11 2:08 pm
Life is a complex pattern on an interupted energy flow.
The planet is not alive, the planet simply is.
2015-11-11 6:22 pm
You are proof the American education system is poor at best.
2015-11-11 3:07 pm
You're confused because there is no one, single thing that makes life. Life needs a variety of conditions (at least as far as we know) in order to exist, including heat, water, etc.
2015-11-11 2:23 pm
I would say carbon, water and energy(sun) are the essentials. However your questions says "our planet". Well our planet is the correct distance from the sun so that water can stay on the surface. It has plenty of carbon too. It also has a magnetic field that keeps harmful radiation away. It it also old enough to have come in contact with bacteria at some point in its history. It also has a moon which helps balance the rotation. We really are very lucky. However, based on the size of the universe, that luck will almost certainly appear elsewhere. It will just be a very long way away, that's all!
2015-11-11 2:08 pm
energy
2015-11-11 4:11 pm
The planet itslef is NOT alive. It is made of dirt and rocks, which are NIOT alive.

But this planet has life ON it.

|WHY this planet has life and others don't is not completely understood by science. It just "is".
2015-11-19 2:15 am
Your ***
2015-11-13 9:12 am
according to islamic mythology every think have been made from water its mentioned in quran and one day this ocean will be explode in the end of world because both hydrogen and oxygen are erupting gases
2015-11-13 8:39 am
Water

"First, you'd need some kind of liquid, any place where molecules can go react," Seager told OurAmazingPlanet. In such a soup, the ingredients for life as we know it, such as DNA and proteins, can swim around and interact with each other to carry out the reactions needed for life to happen.

The most common contender brought up for this solvent is the one life uses on Earth: water. Water is an excellent solvent, capable of dissolving many substances. It also floats when it is frozen, unlike many liquids, meaning that ice can insulate the underlying fluid from freezing further. If water instead sunk when frozen, this would allow another layer of water to freeze and sink, and eventually all the water would get frozen, making the chemical reactions behind life impossible.

Astronomers looking for extraterrestrial life most often focus on planets in the so-called habitable zones of their stars — orbits that are neither too hot nor too cold for liquid water to persist on the surfaces of those worlds. Earth happened to hit the Goldilocks mark, forming within the sun's habitable zone. Mars and Venus lie outside it; if Earth's orbit had been just a bit further inside or outside of where it is, life may likely never have arisen and the planet would be a cold desert like Mars or a cloudy furnace like Venus.

Of course, alien life may not play by the rules we're used to on Earth.

Astrobiologists increasingly suggest looking beyond conventional habitable zones. For instance, while liquid water might not currently persist on the surface of Mars or Venus, there may have been a time when it did. Life might have evolved on their surfaces in that time, and then either fled to safer locales on those planets, such as underground, or adapted to the environment when it became harsh, much as so-called extremophile organisms have on Earth, or both.

In addition, other solvents might host life. "Saturn's moon Titan has liquid methane and ethane." Seager said.

Energy

Second, life needs energy. Without energy, virtually nothing would happen.

The most obvious source of energy is a planet or moon's host star, as is the case on Earth, where sunlight drives photosynthesis in plants. The nutrients created by photosynthesis in turn are what the bulk of life on Earth directly or indirectly relies on for fuel. [50 Amazing Facts About Earth]

Still, countless organisms on Earth subsist on other sources of energy as well, such as the chemicals from deep water vents. There may be no shortage of energy sources for life to live off.

Time

Scientists have argued that habitable worlds need stars that can live at least several billion years, long enough for life to evolve, as was the case on Earth.

Some stars only live a few million years before dying. Still, "life might originate very fast, so age is not that important," astrobiologist Jim Kasting at Pennsylvania State University told OurAmazingPlanet.

For instance, the Earth is about 4.6 billion years old. The oldest known organism first appeared on Earth about 3.5 billion years ago, meaning that life might conceivably evolve in 1.1 billion years or less. However, more complex forms of life did take longer to evolve — the first multicellular animals did not appear on Earth until about 600 million years ago. Because our sun is so long-lived, comparatively, higher orders of life, including humans, had time to evolve.

Recycling

Other researchers have suggested that plate tectonics is vital for a world to host life — that is, a planet whose shell is broken up into plates that constantly move around.

"People talk about plate tectonics as essential in recycling molecules life needs," Seager said. For instance, carbon dioxide helps trap heat from the sun to keep Earth warm. This gas normally gets bound up in rocks over time, meaning the planet would eventually freeze. Plate tectonics helps ensure this rock gets dragged downward, where it melts, and this molten rock eventually releases this carbon dioxide gas back into the atmosphere through volcanoes.

"Plate tectonics is useful but probably not imperative," Kasting said. Seager agreed, saying that "volcanism might very well provide enough fresh supplies of whatever life might need."

Bonus features

Other factors researchers have trotted out for why life succeeded on Earth include how little variation there is in our sun's radiation compared with more volatile stars, or how our planet has a magnetic field that protects us from any storms of charged particles from the sun. Violent bursts of radiation could have scoured life from Earth in its early, fragile stages.

Still, "people are constantly rethinking each of these things and how important they are," Seager said. "We're trying to be less conservative and more open-minded. We want to learn about what gray areas might exist for possible life."

Earth remains the only known planet to host life, due to a unique combination of factors. However, continued monitoring of alien worlds might one day change that, by finding other planets that share these attributes or by discovering other ways that life has found to blossom in the universe.
2015-11-11 9:19 pm
It is just a simple fact. What is the thing that makes a live person alive and a dead person dead? What thing could we inject into a dead body to make it alive? We just don't know the answer to that - not medicine, not science. You can put all of the things the other answers talk about together and have soup. What "the spark of life" is we just don't know. And as usual religion is no help, just dogma.
2015-11-11 4:14 pm
its in the habitable zone
2015-11-11 3:58 pm
There's no one single thing that makes life.... The elements Earth was made from, the distance from the sun, the availability of water, the amount of radiation... they all work in concert to allow life to form, then evolve. You can have identical elements - but at a much greater distance from it's star - and the planet could be in deep freeze. (We see this *almost* with Titan...) Or, conversely - too close to the star, and you'd get something like Venus.
2015-11-11 3:29 pm
Liquid Water & Air. You may not find this combination anywhere else, at the right temperature & pressure
2015-11-11 3:13 pm
The planet is "alive" because of the life it hosts.

Living plants grow and die and thus change Earth's appearance. That gives an illusion that the Earth itself is alive.

Apart from that, there is a seasonal difference in the growth of plants - caused by the 23.5 degree tilt of Earth's axis relative to the orbitalplane around the sun.
https://en.wikipedia.org/wiki/Season
2015-11-11 2:27 pm
sun, water, and carbon dioxide keeps plants alive.
Humans/animals are alive by warmth from the sun, food (from plants), water, and oxygen.

Without humans, animals, and plants, you could say our planet is dead.
2015-11-11 2:22 pm
All life requires an energy source. For Earth that is mostly the sun, but tidal force and volcanic vents are other forms. For hydrocarbon-based life as we know it, liquid water is also a requirement. And for that, an atmosphere is also necessary. Also there needs to be a diverse assortment of other elements to combine with carbon and enable some basic biological functions.


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