Extraterrestrial life

Today, the world is still grappling with a haunting question: Are we alone in this infinite universe, or is life infinitely diverse throughout the universe? To date, we are still alone, but discovering extraterrestrial life would tie a definitive bow on that existential question. In other words, it would be a major paradigm shift. So if we finally determine that we are indeed not alone, will the very fabric of society tear apart?

The universe emits many signals of its own. Black holes send out bursts of radio waves, X-rays and gamma rays. The dusty disks of forming planetary systems shine in infrared waves. Scientists must separate those so-called dumb signals from the smart signals that might come from extraterrestrials. Because of that necessary sifting, they assume that aliens would try to make their messages look different from the natural pings of the universe. Just as you wouldn’t bird-watch in interior Antarctica, you wouldn’t search for aliens in inhospitable environments. Astronomers have discovered thousands of planets, but only a few so far meet our basic requirements for possibly hosting life: being rocky and in the habitable zones around their stars (where water can stay liquid). Here are a few potentially life-friendly star systems where astronomers will aim their alien-seeking telescopes. The star system closest to our sun has a planet — Proxima b — similar to Earth’s mass. No one knows if it has any water, but it’s just 4 light-years away, so maybe we could find out in person someday. he second planet in this star’s solar system is the next-closest Earth-ish-sized planet in a habitable zone, after Proxima b. It’s just 14 light-years from where you’re sitting right now. A mere 22 light-years away, this solar system has three super-Earth planets — between Earth’s and Uranus’ mass — in the habitable zone. And in the hunt for extraterrestrial life, every possibility counts. About 561 light-years away, the fifth planet discovered in this dwarf-star system circles its star’s habitable zone. The planet was the first astronomers found with a size similar to Earth’s. The search for visible-light signals from extraterrestrials is just beginning, as the technology that detects the light inside telescopes becomes more powerful, affordable and able to detect faster flashes. And who knows? Maybe aliens like lasers.

There’s an old saying: “Great discoveries don’t begin with ‘eureka!’ they begin with ‘that’s funny…’”

We can probably put our hopes of meeting aliens on hold just a little bit longer.

A team of researchers studying “Tabby’s star,” a stellar object whose mysterious dips in brightness have puzzled scientists and enthralled space enthusiasts, has announced that the most likely explanation for the behavior is a cloud of fine dust circling the star—wah, wah.

That conclusion is the result of a crowdfunded observational campaign that ran from March 2016 to December 2017, and which caught the telltale fluctuations in brightness on four separate occasions. 

Tabby’s star, officially named KIC 8462852, has been known about for over a century, but it wasn’t until 2015 that it really caught the public’s attention. Tabetha Boyajian, a Louisiana State University astronomer and the source of its nickname, published a paper analyzing data from the Kepler exoplanet-hunting mission that documented massive, irregular dips in the star’s light output. Dips by themselves aren’t necessarily weird — it’s how Kepler looks for exoplanets crossing in front of stars — but one of the dips dimmed the star by 22 percent, far too much to be a planet. Brightness fluctuations that are a result of orbiting bodies usually occur in regular intervals too, but Tabby’s star dimmed unpredictably.

While rumors of an alien megastructure, like a Dyson Sphere, began circulating, astronomers also came up with a multitude of more prosaic reasons for the star’s behavior. A swarm of comets, debris from a planetary collision, a collection of asteroids trailing a planet or processes occurring inside the star could all be responsible for blocking the star’s light, the experts hypothesized.

But let's know about: the messenger from the distant past (Oumuamua)

It's pronounced ‘oh-oo-moo-ah-moo-a.

`Oumuamua rotates rapidly, every 7.3 hours. As it spins, its brightness changes drastically, indicating a highly elongated shape. Karen Meech at the University of Hawaii’s Institute for Astronomy concluded that the asteroid is about 400 meters long but only one-tenth as wide. It’s shaped like a fat cigar, or maybe more like a fire extinguisher–an apt point of comparison, since the asteroid is also very red, similar to some of the objects in our solar system’s distant Kuiper Belt but also broadly similar to some metallic asteroids.

Could it be artificial? 

There could be the obvious giveaways. It might be emitting radio signals or some other artificially modulated form of radiation. (We didn’t see that.) It might adjust its course in some way. (We didn’t see any deviation from a normal gravitational path.) It might give off a heat signature indicating some kind of engine or internal energy source. (We didn’t see that either, although nobody has looked at `Oumuamua in the far infrared.) Then the chatter moved on to more elusive speculations. Could this be a dead, abandoned spaceship? Could it perhaps be instrumented but not actively powered? Artificial objects tend to look artificial. Granted, we knew what to look for when trying to identify an Earth rocket. Granted further, an alien artifact that has been floating through space for millions of years could be heavily altered by radiation and micrometeorites. But still–there’s nothing about `Oumuamua. Which brings me to the final, most exciting point. `Oumuamua is not the end of the story; it is just the beginning. The planet-formation models suggest that one to ten interstellar objects pass through our solar system every year! We haven’t seen them before because they tend to be fast and faint. New tools like the Pan-STARRS survey finally caught one that happened to pass especially close to the sun. Future surveys will be more sensitive, and now scientists will be looking more actively for other visitors to see if they are like `Oumuamua or if they are something else entirely. The Large Synoptic Survey Telescope will be revolutionary in that regard. Right now, `Oumuamua is in a class of one. We don’t know if it is an outlier or if it is somehow typical of the objects that zoom past us from other star systems. Soon, though, we will have a whole catalogue of such objects to study and puzzle over. We will learn about their compositions, their shapes, their trajectories through the galaxy. Already we can see from its motion that `Oumuamua does not seem to be associated with any of the nearby stars. We will see how many interstellar objects are rocky asteroids and how many are icy comets. We will begin to collect direct evidence of what happened to planets in other star systems, so we can compare their history to our own. And maybe, just maybe–I know, I’m inching back onto the crazy train here–but if any of those objects show any sign of artificial origin, there’s an excellent chance we’ll know that, too.

Life in the universe can be seen on the earth:

The findings not only suggest that life on our planet originated some 4 billion years ago, but also help support the increasingly widespread theory that life in the universe is much more common than we previously thought. "By 3.465 billion years ago, life was already diverse on Earth; that’s clear,” said J. William Schopf, a professor of paleobiology at UCLA and the study’s lead author, in a press release. “This tells us life had to have begun substantially earlier, and it confirms that it was not difficult for primitive life to form and to evolve into more advanced microorganisms.” Based on the chemical analysis, the researchers concluded that the 11 fossilized microbes spanned five different taxonomical groups. Some of the microbes were a type of now-extinct bacteria from the domain Archaea, while others were more similar to microbial species still around today. The analysis also suggests that the microbes existed when there was very little oxygen present in Earth’s atmosphere.

If you study all the theories, you may get my word: in the universe & all of a universe may be there and we wouldn’t see, life transfer and separated all over living planet such as earth, but it is the theory too. So who knows what is true, one generation gets it after all. Until then, we can use this tech that there is not a theory of evolution and the big bang. We cant understand them to know. When we learn there is LIGO so there is no gravity when there is life 30bilion years ago so there is not evolution. Be honest with your mind and don’t follow old theories.

 Science will change every second. Be ready