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We Could Find Alien Life, But Politicians Don’t Have The Will



While alien life can be seen nightly on television and in the movies, it has never been seen in space. Not so much as a microbe, dead or alive, let alone a wrinkle-faced Klingon.

Despite this lack of protoplasmic presence, there are many researchers – sober, sceptical academics – who think that life beyond Earth is rampant. They suggest proof may come within a generation. These scientists support their sunny point of view with a few astronomical facts that were unknown a generation ago.

In particular, and thanks largely to the success of NASA’s Kepler space telescope, we can now safely claim that the universe is stuffed with temperate worlds. In the past two decades, thousands of planets have been discovered around other stars. New ones are turning up at the rate of at least one a day.

More impressive than the tally is their sheer abundance. It seems the majority of stars have planets, implying the existence of a trillion of these small bodies in the Milky Way galaxy alone.

A deeper analysis of Kepler data suggests that as many as one in five stars could sport a special kind of planet, one that is the same size as Earth and with similar average temperatures. Such planets, styled as “habitable”, could be swathed by atmospheres and awash in liquid water.

In other words, the Milky Way could be host to tens of billions of Earth’s cousins.

Sterile universe?

It is hard to accept that all these worlds are sterile, a circumstance that would make us, and all the flora and fauna of our planet, a miracle. Miracles have little status in science.

Of course, just because there is a lot of attractive, cosmic real estate doesn’t mean finding inhabitants would be easy. There are only three ways to do that, and they all depend on sophisticated and expensive experiments.

First, we could find life nearby. There is real effort to do that, particularly in our reconnaissance of Mars. So far, most of the search has been indirect: deploying rovers whose job is to locate the best places to dig into the red planet, and possibly uncover either fossilised or extant microbes beneath the sterile surface.

These are not attempts to find life. They are attempts to find places where life could be found. Progress is deliberate, and it is sluggish.

Without doubt, Mars remains the favourite bet for biology. Nonetheless, some experts prefer to wager on the moons of Saturn and Jupiter. At least five of these satellites seem to be home to some sloshy environments – mostly liquid water, although in the case of Titan, natural gas.

Again, the type of life that could best thrive on these moons would be microscopic. Sensing its presence might be accomplished in several ways, ranging from simple flyby missions that nab effluvia from natural geysers, to sending elaborate drilling rigs to penetrate the ten miles of ice that separate the surface of Jupiter’s moon Europa from the mammoth seas that lie below.

Sadly much of this reconnaissance hardware is still on the drawing boards, not in space. Progress is slow, mostly because funding is low.

A second scheme for sniffing out evidence of biology is to assay the atmospheres of planets around other stars. This is done using a time-honoured technique of astronomy, spectroscopy – an approach that would allow researchers to learn the composition of an atmosphere at many light-years’ distance.

While an experiment to find oxygen or methane in someone else’s air is straightforward to describe, it is hard to do. That is because planets are dim, and the stars they orbit are bright.

Various solutions to this problem have been imagined, including multi-element, orbiting telescopes and giant light blockers, or occulters, in space. It is rocket science, but it is not as hard as curing the common cold. Engineers could build this stuff within a dozen years, but only if they had the money.

The third approach to finding biology beyond Earth is looking beyond microbes for intelligent life by eavesdropping on radio signals or flashing laser lights. More antennae and better receivers could speed up this search, but once again, funding is the limiting factor.

So it boils down to this: we don’t know for certain that there is life in space, but the circumstances of the universe certainly suggest that this is a plausible idea. Finding it would be extraordinarily exciting, but because the payoff is uncertain, the investments in searching have been modest.

Of course, if you don’t ante up, you will never win the jackpot. And that is a question of will.

Seth Shostak, Senior Astronomer, SETI Institute

This article is republished from The Conversation under a Creative Commons license. Read the original article

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Extraterrestrial life may be hiding in “terminator zones”




In a study published in the Astrophysical Journal, astrophysicists set out to find out if exoplanets could support life.

Astronomers have come to the conclusion that on the surface of some exoplanets there is a strip that may contain water, necessary for the existence of biological life. The terminator zone is the dividing line between the day and night sides of an exoplanet.

Many exoplanets are planets outside the solar system held by gravity. This means that one side of the planet is always facing the star they orbit, while the other side is in constant darkness.

The water on the dark side will most likely be in a frozen state, while on the light side it will be so hot that the water should just evaporate.

The terminator zone would be a “friendly place” – neither too hot nor too cold – in which liquid water could support extraterrestrial life.

Dr. Ana Lobo of the University of California, said: “The day side can be scalding hot, much uninhabitable, while the night side will be icy, potentially covered in ice. You need a planet that’s the right temperature for liquid water.”

“We’re trying to draw attention to planets with more limited amounts of water that, despite not having widespread oceans, might have lakes or other smaller bodies of liquid water, and that climate could actually be very promising.”

“By exploring these exotic climate states, we are improving our chances of finding and correctly identifying a habitable planet in the near future.”

The researchers created a model of their climate by analyzing different temperatures, wind patterns and radiative forcing, and found the “correct” zone on exoplanets that could contain life-supporting liquid water.

Researchers who are looking for life on exoplanets will now take into account the fact that it can hide in certain areas.

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Astronomers discover the strongest evidence for another Universe before the Big Bang




The notion of the Big Bang goes back nearly 100 years, when the first evidence for the expanding Universe appeared.

If the Universe is expanding and cooling today, that implies a past that was smaller, denser, and hotter. In our imaginations, we can extrapolate back to arbitrarily small sizes, high densities, and hot temperatures: all the way to a singularity, where all of the Universe’s matter and energy was condensed in a single point. 

For many decades, these two notions of the Big Bang — of the hot dense state that describes the early Universe and the initial singularity — were inseparable.

But beginning in the 1970s, scientists started identifying some puzzles surrounding the Big Bang, noting several properties of the Universe that weren’t explainable within the context of these two notions simultaneously. 

When cosmic inflation was first put forth and developed in the early 1980s, it separated the two definitions of the Big Bang, proposing that the early hot, dense state never achieved these singular conditions, but rather that a new, inflationary state preceded it. 

There really was a Universe before the hot Big Bang, and some very strong evidence from the 21st century truly proves that it’s so.

Although we’re certain that we can describe the very early Universe as being hot, dense, rapidly expanding, and full of matter-and-radiation — i.e., by the hot Big Bang — the question of whether that was truly the beginning of the Universe or not is one that can be answered with evidence. 

The differences between a Universe that began with a hot Big Bang and a Universe that had an inflationary phase that precedes and sets up the hot Big Bang are subtle, but tremendously important. After all, if we want to know what the very beginning of the Universe was, we need to look for evidence from the Universe itself.

Read the full article here.

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