1. Are we alone in the universe?
Answers
Answer:
Are we alone? Might Earth be the sole exception to an otherwise dead universe? We shouldn’t be. The ingredients for life are everywhere — life should be common. But then, where is everyone?
This article explains the three possible answers to this question. By the time you finish reading, you will have a firm grasp of the relevant science, enough to form an opinion on which answer is probably right.
Requirements of Life
To arise, life needs three things: Matter, Energy, and Time.
All can be found wherever there are stars. Each star is like a scratch-off lottery ticket — a chance to win by having the right combination. The prize: the universe gains a new planet full of life.
The chance a ticket pays off remains unknown, but science has made progress in estimating the odds.
Given the huge number of tickets, (there are 10^{22}10
22
stars in the observable universe), the chances seem good that more than one has paid off.
Let’s review the specific requirements life has for matter, energy and time.
Matter
Matter is the stuff life is made of, the building blocks. These are the chemical elements — hydrogen, oxygen, carbon, nitrogen, and so on. These elements exist everywhere. They’re created as byproducts of fusion — the ash of nuclear fires which burn in every star.
The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star stuff.
Carl Sagan
Hydrogen, oxygen, carbon, and nitrogen make up over 99% of the atoms in our bodies. The others are needed only in trace amounts. These same four elements that compose the bulk of our bodies are also the most common chemically-active elements in the solar system.
The same physics and chemistry that operate here apply everywhere in the universe. The familiar elements on Earth are found in every star and galaxy we see. This is more than conjecture. Through analysis of light astronomers can determine the chemical composition of far away stars, nebulae, and galaxies.
Radio telescopes can detect the presence of organic molecules in the center of the Milky Way Galaxy
The ALMA observatory detected complex organic molecules in a gas cloud 27,000 light years away. Image Credit: Y. Beletsky (LCO)/ESO
Complex organic (carbon-containing) molecules, the precursors to life including amino acids, have been detected in distant star-forming gas clouds, or stellar nurseries near the center of the galaxy.
So you are made of the same stuff as stars, planets, comets and gas clouds.
Given the availability of these vital ingredients, the whole universe is filled with the matter needed for life. But life still needs energy and enough time to evolve.
Energy
All life feeds on energy. Energy forestalls the natural tendency towards disorder. Any time order is created, such as in growing a body, energy must be expended.
Plants obtain energy from sunlight and store it in chemical bonds. Animals get energy from plants, by eating them and breaking those bonds to release energy, or they eat other animals.
The energy that drives the entire food chain and powers all living things on Earth started in the core of our sun. The same fusion responsible for cooking the chemicals of life provides stars, and life, their energy.
Though all life needs energy, not every life form gets it from sunlight.
Europa, one of Jupiter’s moons, appears on the surface to be a frozen ball of ice. But scientists believe that 10 miles under its frozen surface lies an ocean with twice the liquid water of Earth’s oceans.
What provides the energy to melt this ice? The tides!
Tidal friction creates heat that could melt the ice and provide energy for life. Ultimately this energy comes from the spinning of Jupiter. As Europa’s own tidal forces drag on Jupiter, Jupiter’s rotation slows and its days become longer.
The oldest known lifeforms used geothermal, rather than solar energy. They got their energy from hydrothermal vents like the Lost City — undersea geysers powered by the heat of Earth’s interior.
Life uses energy wherever it finds it.
Answer:
no we aren't alone in the universe
Explanation:
There are many stars , planets , galaxies.........etc
Hope it helps
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