₦airaland Forum

I would love to meditate in this room.

https://www.youtube.com/watch?v=rzB2R_qiC28

A high resolution image of a Solar Eclipse!

A cool online resource for Introductory Physics: https://courses.lumenlearning.com/physics/

A001:

Gravity and radiation will be the difficult things to overcome.

Studies from the ISS show that humans loose bone and muscle mass at zero G without constant exercise. We don't know what the effects of 1/3 earth gravity will have on the human body.

To combat radiation, some have come up with the idea of underground habitats.

IMAliyu:
Gravity and radiation will be the difficult things to overcome.

Studies from the ISS show that humans loose bone and muscle mass at zero G without constant exercise. We don't know what the effects of 1/3 earth gravity will have on the human body.

To combat radiation, some have come up with the idea of underground habitats.

Sounds interesting

https://www.youtube.com/watch?v=FSEJ4YLXtt8

Do the laws of physics and neuroscience disprove free will?

Many have argued that free will is in illusion, but science does not support that.

-Are we free to make our own choices, or are we automatons controlled by some mysterious conductor?

-Until recently, a debate raged in neuroscience circles concerning this very question because an experiment showed that the brain decides before we are aware of it.

-Fortunately, the experiment was recently debunked, leaving us to face the hard reality that we must be responsible for our actions. Choose wisely.

Are we free to make choices or are we automatons in a giant and invisible cosmic machinery, cogs and wheels turning about, not knowing why we make the choices we make?

This is a thorny question that has important consequences, and not just for law enforcement.

Of course, we all want to be free, even if freedom is a very difficult idea to define — firstly because no one is completely free. We all have our professional, family, and social commitments.

We grow up within cultural norms. In a sense, to be free is to be able to choose to what we are going to commit.

Most people believe that they are free to choose what to do, from the simplest to the more complex: Should I drink coffee with sugar or sweetener?

Do I put some money in savings, or do I spend it all? Or, as a friend of mine likes to say, “Should I get married or buy a bicycle?”

The question of free will is essentially a question of agency, of who is in charge as we go through our lives making all sorts of choices.

Traditionally, it has been a topic for philosophers and theologians. In the Old Testament, free will became an option after the Fall, when Adam and Even were kicked out of Eden for eating the apple of knowledge.

This seems to imply that with knowledge comes the independence to make choices and the freedom to act according to your will. There are good and bad choices, and the bad ones will cost you dearly, if not in this life, then in the afterlife.

Even if you don’t subscribe to this particular narrative, the point is that choices come with consequences.

If there is no free will, if we are indeed automatons of sorts, then to what extent are we really choosing when we think we are?

And if we are not choosing, what or who is? And if we are not choosing, why do we have this notion or feeling that we are?

A clockwork universe
Early in the 19th century, the idea that the universe was a giant clockwork mechanism was all the rage (at least for the intellectual elite).

The French mathematical physicist, Pierre-Simon Laplace, had beautifully refined Newton’s physics to describe, in quantitative detail, the formation of the Solar System and planets and the stability of the planetary orbits around the Sun.

They all followed precise quantitative laws that were able to predict when Halley’s comet would return and when and where the next total solar eclipse would occur, among many other astronomical phenomena.

Laplace even speculated that if a super-mind had the power to know the positions and velocities of every particle in the universe at the same moment of time, it would be able to predict the future for all eternity — even the fact that I wanted to write about free will today and that you would be reading this.

Legend tells that when Laplace gave a copy of his book Celestial Mechanics to Napoleon, the emperor saluted him on his accomplishment but also asked, “Why is there no God in your cosmos?” Laplace replied, “Because I have no need for this hypothesis.”

That is the apex of deterministic reasoning and why people thought free will was a goner. Laplace probably knew, I suspect, that it was all hubris. But it was impressive for sure.

Neuroscience and free will
Fortunately, the mind is not a solar system with strict deterministic laws. We have no clue what kinds of laws it follows, apart from very simplistic empirical laws about nerve impulses and their propagation, which already reveal complex nonlinear dynamics.

Still, work in neuroscience has prompted a reconsideration of free will, even to the point of questioning our freedom to choose. Many neuroscientists and some philosophers consider free will to be an illusion. Sam Harris, for example, wrote a short book arguing the case.

This shocking conclusion comes from a series of experiments that revealed something quite remarkable: Our brains decide a course of action before we know it.

Benjamin Libet’s pioneering experiments in the 1980s using EEG and more recent ones using fMRI or implants directly into neurons found that the motor region responsible for making a motion in response to a question fired up seven seconds before the subject was aware of it.

The brain seems to be deciding before the mind knows about it. But is it really?

The experiment has been debunked, which actually is far from surprising. But what was surprising was the huge amount of noise that the claims against free will emerging from this type of experiment generated.

To base the hefty issue of free will on experiments that measure neuronal activity when people move fingers to push a button should hardly count as decisive. Most of the choices we make in life are complex, multi-layered decisions that often take a long time.

Be thankful for free will
This should be a relief to most people, for many reasons. First, we are definitely not automatons without choice.

Second, we actually do need to take responsibility for our actions, from wasting water in a long shower to shooting someone dead.

There is no cosmic machinery making us do stuff, one way or the other.

This means that we must face up to the way we live our lives and how we relate to each other and to the planet, knowing that our choices do have consequences that go beyond our small bubble of being.

Source: https://bigthink.com/13-8/physics-neuroscience-free-will/

Pythagoras’ Revenge: Humans Didn’t Invent Mathematics, It’s What the Physical World Is Made Of

Many people think that mathematics is a human invention. To this way of thinking, mathematics is like a language: it may describe real things in the world, but it doesn’t “exist” outside the minds of the people who use it.

But the Pythagorean school of thought in ancient Greece held a different view. Its proponents believed reality is fundamentally mathematical.

More than 2,000 years later, philosophers and physicists are starting to take this idea seriously.

As I argue in a new paper, mathematics is an essential component of nature that gives structure to the physical world.

Honeybees and hexagons

Bees in hives produce hexagonal honeycomb. Why?

According to the “honeycomb conjecture” in mathematics, hexagons are the most efficient shape for tiling the plane.

If you want to fully cover a surface using tiles of a uniform shape and size, while keeping the total length of the perimeter to a minimum, hexagons are the shape to use.

Charles Darwin reasoned that bees have evolved to use this shape because it produces the largest cells to store honey for the smallest input of energy to produce wax.

The honeycomb conjecture was first proposed in ancient times, but was only proved in 1999 by mathematician Thomas Hales.

Cicadas and prime numbers

Here’s another example. There are two subspecies of North American periodical cicadas that live most of their lives in the ground. Then, every 13 or 17 years (depending on the subspecies), the cicadas emerge in great swarms for a period of around two weeks.

Why is it 13 and 17 years? Why not 12 and 14? Or 16 and 18?

One explanation appeals to the fact that 13 and 17 are prime numbers.

Some cicadas have evolved to emerge from the ground at intervals of a prime number of years, possibly to avoid predators with life cycles of different lengths.

Imagine the cicadas have a range of predators that also spend most of their lives in the ground. The cicadas need to come out of the ground when their predators are lying dormant.

Suppose there are predators with life cycles of 2, 3, 4, 5, 6, 7, 8 and 9 years. What is the best way to avoid them all?

Well, compare a 13-year life cycle and a 12-year life cycle. When a cicada with a 12-year life cycle comes out of the ground, the 2-year, 3-year and 4-year predators will also be out of the ground, because 2, 3 and 4 all divide evenly into 12.

When a cicada with a 13-year life cycle comes out of the ground, none of its predators will be out of the ground, because none of 2, 3, 4, 5, 6, 7, 8 or 9 divides evenly into 13. The same is true for 17.

P1–P9 represent cycling predators. The number-line represents years. The highlighted gaps show how 13 and 17-year cicadas manage to avoid their predators. Credit: Sam Baron

It seems these cicadas have evolved to exploit basic facts about numbers.

Creation or discovery?

Once we start looking, it is easy to find other examples. From the shape of soap films, to gear design in engines, to the location and size of the gaps in the rings of Saturn, mathematics is everywhere.

If mathematics explains so many things we see around us, then it is unlikely that mathematics is something we’ve created. The alternative is that mathematical facts are discovered: not just by humans, but by insects, soap bubbles, combustion engines and planets.

What did Plato think?

But if we are discovering something, what is it?

The ancient Greek philosopher Plato had an answer. He thought mathematics describes objects that really exist.

For Plato, these objects included numbers and geometric shapes. Today, we might add more complicated mathematical objects such as groups, categories, functions, fields and rings to the list.

Abstract Numbers Visual

For Plato, numbers existed in a realm separate from the physical world.

Plato also maintained that mathematical objects exist outside of space and time. But such a view only deepens the mystery of how mathematics explains anything.

Explanation involves showing how one thing in the world depends on another. If mathematical objects exist in a realm apart from the world we live in, they don’t seem capable of relating to anything physical.

Enter Pythagoreanism

The ancient Pythagoreans agreed with Plato that mathematics describes a world of objects. But, unlike Plato, they didn’t think mathematical objects exist beyond space and time.

Instead, they believed physical reality is made of mathematical objects in the same way matter is made of atoms.

If reality is made of mathematical objects, it’s easy to see how mathematics might play a role in explaining the world around us.

In the past decade, two physicists have mounted significant defenses of the Pythagorean position: Swedish-US cosmologist Max Tegmark and Australian physicist-philosopher Jane McDonnell.

Tegmark argues reality just is one big mathematical object. If that seems weird, think about the idea that reality is a simulation. A simulation is a computer program, which is a kind of mathematical object.

McDonnell’s view is more radical. She thinks reality is made of mathematical objects and minds. Mathematics is how the Universe, which is conscious, comes to know itself.

I defend a different view: the world has two parts, mathematics and matter. Mathematics gives matter its form, and matter gives mathematics its substance.

Mathematical objects provide a structural framework for the physical world.

The future of mathematics

It makes sense that Pythagoreanism is being rediscovered in physics.

In the past century, physics has become more and more mathematical, turning to seemingly abstract fields of inquiry such as group theory and differential geometry in an effort to explain the physical world.

As the boundary between physics and mathematics blurs, it becomes harder to say which parts of the world are physical and which are mathematical.

But it is strange that Pythagoreanism has been neglected by philosophers for so long.

I believe that is about to change. The time has arrived for a Pythagorean revolution, one that promises to radically alter our understanding of reality.
Source: https://scitechdaily.com/pythagoras-revenge-humans-didnt-invent-mathematics-its-what-the-physical-world-is-made-of/amp/

A001:

What's the essence of these things??

A001:
[/quote][quote]

Life doesn't still make sense to me....

Can you help my brother?


You're free to ask questions.....

JWST: The James Webb Space Telescope

NASA launches first dedicated X-ray mission to study the polarization of extreme cosmic objects


NASA has launched a mission to measure the X-ray polarization from the most extreme and mysterious objects in the universe.

The $188m Imaging X-ray Polarimetry Explorer (IXPE) was launched today from the Kennedy Space Center at 01:00 local time aboard a Falcon 9 rocket.

During the probe’s two-year mission, it will study several astrophysical phenomena including black holes, active galactic nuclei, quasars, pulsars and supernova remnants.

Following a successful launch and separation, IXPE is now in orbit around the equator at an altitude of around 600 km above Earth.

This particular orbit will minimize the X-ray instrument’s exposure to radiation in the South Atlantic Anomaly, the region where the inner Van Allen radiation belt comes closest to Earth’s surface.

The mission contains three identical telescopes, which are able to operate independently and that each have polarization-sensitive detectors.

The craft will use these to provide simultaneous spectral, spatial, and temporal measurements of cosmic sources with scientists aiming to improve the polarization sensitivity by two orders of magnitude over the X-ray polarimeter aboard the Orbiting Solar Observatory OSO-8, which was launched in 1975.

Astronomers hope this will allow them to determine the geometry and the emission mechanism of active galactic nuclei and microquasars as well as find the magnetic field configuration in magnetars.

It is an indescribable feeling to see something you’ve worked on for decades become real and launch into space

“IXPE represents another extraordinary first,” says Thomas Zurbuchen, associate administrator for NASA’s science mission directorate.

“IXPE is going to show us the violent universe around us – such as exploding stars and the black holes at the center of galaxies – in ways we’ve never been able to see it. [It] will shape our understanding of the universe for years to come.”

Developed by NASA’s Small Explorer programme, IXPE is a collaboration between NASA and the Italian Space Agency and was selected in January 2017 with a launch date in May 2021.

However, that was delayed due to the impact of the COVID-19 pandemic.

“It is an indescribable feeling to see something you’ve worked on for decades become real and launch into space,” says IXPE’s principal investigator Martin Weisskopf, who helped to concieve and build the spacecraft.

“This is just the beginning for IXPE. We have much work ahead.”

Source: https://physicsworld.com/a/nasa-launches-first-dedicated-x-ray-mission-to-study-the-polarization-of-extreme-cosmic-objects/

What is the Fermi Paradox?

The Fermi Paradox asks "Where is everybody?"

The Fermi Paradox refers to the dichotomy between the high probability that extraterrestrial intelligence exists and the fact that we have no evidence for such aliens.

This paradox was described by the late British science-fiction author, Sir Arthur C. Clarke, who said: "Two possibilities exist: Either we are alone in the universe or we are not. Both are equally terrifying."

Many experts since have grappled with the same question.

Why, considering the multitude of planets and stars in the Milky Way, have we not heard from anyone?

We call this problem the Fermi Paradox, and there are a number of possible solutions — some more unnerving than others …

WHAT IS THE FERMI PARADOX?

The Fermi Paradox is a problem that asks, where are all the aliens in the universe? If life is so abundant, why haven't we been visited by, or heard from, anyone else?

According to NASA, in just the last two decades we have found more than 4,000 planets beyond our solar system, with trillions of stars thought to exist in our galaxy — most of which host their own planets.

Considering life sprang up on Earth, would we not have expected it to start in at least one other location in the last 14 billion years of the universe?

WHO CAME UP WITH THE FERMI PARADOX?

The Fermi Paradox was devised by the Italian-American physicist Enrico Fermi, according to the Planetary Society.

He is said to have come up with the idea in a throwaway remark over lunch with colleagues in 1950 when he asked "Where is everybody?"

He wondered, given that our planet was relatively young compared to the universe, we might have expected someone to have visited us by now — but we had no evidence of that ever occurring.

Fermi died four years later, in 1954, so did not have long to ponder the question.

But his idea has sparked whole fields of science hoping to solve the problem, including the search for extraterrestrial intelligence (SETI).

WHAT ARE THE SOLUTIONS TO THE FERMI PARADOX?

There are a number of solutions to the Fermi Paradox. The most obvious, and likely, is that we simply haven't looked hard enough to find other life, and interstellar travel between stars is difficult.

The first planets beyond our own solar system were only discovered in the 1990s. This means we have barely started to scratch the surface of studying other worlds.

For example, we are yet to find many planets that look exactly like Earth, orbiting stars like our sun — but upcoming telescopes are hoped to be capable of such detections in the coming decade or two.

Even then, the distances between star systems are enormous, making journeys between them difficult. Our closest star system for example, Alpha Centauri, is four light-years away.

The distance from Earth to Neptune, for comparison, is 0.0005 light-years — a journey that would still take us decades with current technology.

Intelligent aliens might simply have decided to never visit us, or did so long ago without leaving any trace.

Alternatively, it might be that life is simply so rare that the chances of two intelligent species being positioned relatively near each other in the vastness of space is exceedingly slim.

A more somber suggestion is that we are alone in the universe. Life, like that found on Earth, is simply so vanishingly unlikely to arise, that ours was the only world where this happened.

Most scientists think this is unlikely. But there is the possibility that some sort of event, known as a Great Filter, might prevent civilizations like our own from progressing far enough to make contact elsewhere.

WHAT IS THE GREAT FILTER?

The Great Filter is the idea that catastrophic events, either manmade or natural, cause intelligent life to be extinguished on habitable worlds before they have a chance to extend their reach into the universe.

These events could be one of many things. They might be powerful solar flares, climate change, asteroid impacts, or perhaps something of the planet's own doing like a nuclear apocalypse.

If this idea is correct, it's not clear if we have already passed this filter — or we are yet to reach it …

WHAT IS THE DRAKE EQUATION?

The Drake equation is an idea, proposed by the American astronomer Frank Drake in 1961, that the number of potential civilizations in the universe can be calculated if we know a few key variables.

The formula for the Drake equation is:

N = R* x �p x ne x �1 x �i x �c x L

R* = average rate of star formation in Milky Way

�p = fraction of stars supporting planets

ne = average number of planets that could potentially support life for each star that hosts planets

�1 = fraction of those planets that "could" support life that actually develop life

�i = fraction of planets that develop intelligent life, and thus intelligent civilizations

�c = fraction of those civilizations that develop a technology to communicate their existence

L = length of time over which these civilizations send those detectable signals into space

By including all of these factors in the equation, the idea is you might be able to work out how many other intelligent civilizations exist in the universe.

This "simple" formula, Drake once said, would be akin to estimating the number of students at a university by multiplying the number of new students entering each year by the average number of years a student will spend at a university, according to SETI.

As of yet, however, a number of key variables in the equation remain unknown, meaning we can't yet come up with a possible number for other species of intelligent life.

CAN WE SOLVE THE FERMI PARADOX?

Many scientists hope that we can solve the Fermi Paradox. Upcoming telescopes, like NASA's James Webb Space Telescope launching in December 2021, will be able to study the atmospheres of exoplanets like never before, while the search for new planets is continuing unabated.

By finding more planets in habitable zones around their stars, where temperatures are just right for liquid water to exist, scientists could narrow down the possibility of other Earth-like worlds in the universe — and, by using advanced telescopes, study some of these Earth-like orbs in our galaxy.

Ultimately, scientists simply need more data in order to truly understand the Fermi Paradox. But if it turns out that habitable planets are common, and astronomers are still yet to hear from anyone, then it might suggest intelligent life such as that on Earth is rare.

ARE WE ALONE IN THE UNIVERSE?

We don't know if we are alone in the universe, but scientists hope to answer this question in the coming years.

Ongoing missions, like NASA's Perseverance rover on Mars, could give us vital clues. Perseverance is collecting samples that will be returned to Earth in the 2030s and could contain signs of past or present life on Mars.

If we can discover even simple life on Mars or another location, like an icy moon of Jupiter or Saturn such as Europa and Enceladus, that would be proof that life had sprung up in at least two locations — Earth and this other world.

In that instance, it would suggest life is not just limited to our own planet. With that, it would raise the prospect that other intelligent life, like us, might well exist in our galaxy and beyond.

Source: https://www.livescience.com/fermi-paradox
Cc: OtemAtum

OtemAtum, what key things do you think scientists are missing in the Search for Extraterrestrial Intelligence (SETI)?

If other beings (human-like entities, animals, plants) exist on other planets as you say, why haven't they made contact with us? Are they hiding from us?

What do you think about the Great Filter? Do you think the Homo Erectus epoch also faced the same problem of Great Filter?

Sorry for my plenty questions. Kindly answer them and the one on your main thread.

Thanks.

Drake Equation

How many alien societies exist, and are detectable?

This famous formula (equation above) gives us an idea. The Drake Equation, which was the agenda for a meeting of experts held in West Virginia in 1961, estimates N, the number of transmitting societies in the Milky Way galaxy. The terms are defined in the images above.

Understanding the Drake Equation

This simple formulation is generally agreed to be the “second most-famous equation in science (after E= mc2),” and you can find it in nearly every astronomy textbook.

The Drake Equation was cooked up by astronomer Frank Drake in 1961 to serve as the agenda for the first meeting on the topic of SETI.

In 1960, Drake had conducted a pioneering search for extraterrestrial signals – a several-week long effort he named Project Ozma.

Somewhat unexpectedly, this modest experiment attracted a great deal of attention, and Drake was encouraged by J.P.T. Pearman, a staff officer at the National Academy of Sciences, to organize an informal gathering of accomplished researchers and engineers to discuss the prospects for finding a signal.

Was listening for radio signals a worthy endeavor or not?

Approximately a dozen people attended this informal meeting, and they all were eminent.

Among them was biochemist Melvin Calvin (who received a call during the meeting notifying him that he had just won the Nobel Prize), biologist Joshua Lederberg, physicist Philip Morrison, and planetary astronomer Carl Sagan, as well as Peter Pearman and self-invited guest Barney Oliver, a highly accomplished radio engineer.

The conference took place at the Green Bank Observatory – the site of Project Ozma – in November 1961.

While planning the event, Drake chose to organize the discussion around a simple formula he concocted that estimated a critical number for SETI, namely the estimated count of transmitting worlds in the Galaxy.

His equation is comprised of seven factors which, when multiplied together, yield the number of societies that are now broadcasting signals one might conceivably pick up. The factors are listed and defined above.

As Drake himself has noted, his simple formula can be likened to how you might estimate the number of students at a university.

All you need to do is consider the number of new students (freshmen) entering each year and multiply that by the average number of years the students will spend at the school (four years.) Voila, you have a good estimate of the total number of undergraduate students.

The Drake Equation is constructed with similar logic. The first six terms, when multiplied together, yield the average number of new technologically transmitting societies that come on-line in the Milky Way galaxy each year.

This “freshman” rate is then multiplied by the equation’s last term, L: the average lifetime they stay on the air. The result is N, the average number of transmitting societies in the Galaxy now.

Clearly, if this number is very small, then the chances of a signal detection by SETI are also small. Conversely, a large value of N would be incentive to press the search.

At the time of the meeting, essentially none of the seven factors in the equation was known excepting the first, the production rate of stars.

Nonetheless, the attendees bandied about their best guesses for the other terms, concluding that the “freshman” rate was on the order of one.

In other words, new transmitting societies appear once a year somewhere in the Milky Way. All that remains is to multiply this by the lifetime of such a broadcasting civilization.

This last term, L, is obviously dependent on alien behavior. It’s not a factor we can quantify with studies in astronomy or biology.

Our own experience also doesn’t help much. We’ve been transmitting on a widescale basis, and at frequencies and powers that might conceivably be picked up by someone in another solar system, for less than a century.

How long will we continue to do this? Some people think that humanity is hellbent on self-annihilation, and the value of L for Homo sapienswill be merely a century or two. Others are less dramatic and more optimistic.

But obviously we have little basis for estimating L.

Due to such uncertainties, estimates for N have ranged from 1 (Earth houses the only galactic society that is transmitting) to several million, Drake himself currently suggests that N = 10,000 (the consequence of assuming that new transmitting societies are produced at intervals of one per year and enjoy an average lifetime of 10,000 years).

It has been sixty years since the Drake Equation was conceived. Have we nailed down more of the terms than the single one known in 1961?

Sadly, no. In fact, we’ve made little progress in this regard apart from the terms giving the fraction of new stars sporting planets, and (to a lesser degree) the average number of planets per solar system suitable for complex life.

The attendees of the 1961 Green Bank meeting thought it likely that the former was close to 100 percent, and the latter was approximately one.

Both guesses are within a factor of two or three of modern estimates, based on the discoveries of thousands of exoplanets since 1995.

It’s worth noting that many people have suggested amendments to the Drake Equation, adding terms to account for facts that don’t seem to be part of the original formula, such as colonization of other star systems by ambitious societies.

Others have proffered changes to the math, replacing single terms with mathematical distributions. But according to Drake, none of these refinements is necessary nor do they alter the equation in any essential and substantive way.

While the Drake Equation cannot be “solved” or even accurately calculated, it retains considerable utility for discussions about extraterrestrial life and intelligence.

And that, after all, was the reason for its invention. It’s also noteworthy that this famous formulation encompasses all the research activities of the SETI Institute, from our efforts to probe the harsh landscapes of Mars to our extremely high-tech searches for alien signals. It is the scaffolding upon which the Institute has been built.

There are 100 scientists at the SETI Institute, working on nearly 100 research questions. But each of these topics can be related to one of the terms in the Drake Equation.

N: Are technological societies common or not? Our ATA radio telescope is looking for signals coming from other star systems that would help answer that question.

Source: https://www.seti.org/drake-equation-index

Frank Drake's image below:

Are we alone in the universe? Revisiting the Drake equation


A revised version of the Drake equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe.

Are humans unique and alone in the vast universe? This question--summed up in the famous Drake equation--has for a half-century been one of the most intractable and uncertain in science.

But a new paper shows that the recent discoveries of exoplanets combined with a broader approach to the question makes it possible to assign a new empirically valid probability to whether any other advanced technological civilizations have ever existed.

And it shows that unless the odds of advanced life evolving on a habitable planet are astonishingly low, then human kind is not the universe’s first technological, or advanced, civilization.

The paper, published in Astrobiology, also shows for the first time just what “pessimism” or “optimism” mean when it comes to estimating the likelihood of advanced extraterrestrial life.

“The question of whether advanced civilizations exist elsewhere in the universe has always been vexed with three large uncertainties in the Drake equation,” said Adam Frank, professor of physics and astronomy at the University of Rochester and co-author of the paper.

“We’ve known for a long time approximately how many stars exist. We didn’t know how many of those stars had planets that could potentially harbor life, how often life might evolve and lead to intelligent beings, and how long any civilizations might last before becoming extinct.”

“Of course, we have no idea how likely it is that an intelligent technological species will evolve on a given habitable planet,” says Frank.

"But using our method we can tell exactly how low that probability would have to be for us to be the ONLY civilization the Universe has produced. We call that the pessimism line. If the actual probability is greater than the pessimism line, then a technological species and civilization has likely happened before.”

Using this approach, Frank and Sullivan calculate how unlikely advanced life must be if there has never been another example among the universe’s ten billion trillion stars, or even among our own Milky Way galaxy’s hundred billion.

"Rather than asking how many civilizations may exist now, we ask ‘Are we the only technological species that has ever arisen?'"
- Woodruff Sullivan, University of Washington

The result? By applying the new exoplanet data to the universe’s 2 x 10 to the 22nd power stars, Frank and Sullivan find that human civilization is likely to be unique in the cosmos only if the odds of a civilization developing on a habitable planet are less than about one in 10 billion trillion, or one part in 10 to the 22nd power.

“One in 10 billion trillion is incredibly small,” says Frank.

“To me, this implies that other intelligent, technology producing species very likely have evolved before us. Think of it this way.

Before our result you’d be considered a pessimist if you imagined the probability of evolving a civilization on a habitable planet were, say, one in a trillion.

But even that guess, one chance in a trillion, implies that what has happened here on Earth with humanity has in fact happened about a 10 billion other times over cosmic history!”

For smaller volumes the numbers are less extreme.

For example, another technological species likely has evolved on a habitable planet in our own Milky Way galaxy if the odds against it evolving on any one habitable planet are better than one chance in 60 billion.

But if those numbers seem to give ammunition to the “optimists” about the existence of alien civilizations, Sullivan points out that the full Drake equation—which calculates the odds that other civilizations are around today—may give solace to the pessimists.

“Thanks to NASA's Kepler satellite and other searches, we now know that roughly one-fifth of stars have planets in “habitable zones,” where temperatures could support life as we know it. So one of the three big uncertainties has now been constrained.”

Frank said that the third big question--how long civilizations might survive--is still completely unknown.

“The fact that humans have had rudimentary technology for roughly ten thousand years doesn’t really tell us if other societies would last that long or perhaps much longer,” he explained.

But Frank and his coauthor, Woodruff Sullivan of the astronomy department and astrobiology program at the University of Washington, found they could eliminate that term altogether by simply expanding the question.

“Rather than asking how many civilizations may exist now, we ask ‘Are we the only technological species that has ever arisen?" said Sullivan.

“This shifted focus eliminates the uncertainty of the civilization lifetime question and allows us to address what we call the ‘cosmic archaeological question’—how often in the history of the universe has life evolved to an advanced state?”

That still leaves huge uncertainties in calculating the probability for advanced life to evolve on habitable planets.

It's here that Frank and Sullivan flip the question around.

Rather than guessing at the odds of advanced life developing, they calculate the odds against it occurring in order for humanity to be the only advanced civilization in the entire history of the observable universe.

With that, Frank and Sullivan then calculated the line between a Universe where humanity has been the sole experiment in civilization and one where others have come before us.

In 1961, astrophysicist Frank Drake developed an equation to estimate the number of advanced civilizations likely to exist in the Milky Way galaxy.

The Drake equation (top row) has proven to be a durable framework for research, and space technology has advanced scientists' knowledge of several variables.

But it is impossible to do anything more than guess at variables such as L, the probably longevity of other advanced civilizations.

In new research, Adam Frank and Woodruff Sullivan offer a new equation (bottom row) to address a slightly different question: What is the number of advanced civilizations likely to have developed over the history of the observable universe?

Frank and Sullivan's equation draws on Drake's, but eliminates the need for L.

Their argument hinges upon the recent discovery of how many planets exist and how many of those lie in what scientists call the “habitable zone” – planets in which liquid water, and therefore life, could exist. This allows Frank and Sullivan to define a number they call Nast.

Nast is the product of N*, the total number of stars; fp, the fraction of those stars that form planets; and np, the average number of those planets in the habitable zones of their stars.

They then set out what they call the “Archaelogical-form” of the Drake equation, which defines A as the “number of technological species that have ever formed over the history of the observable Universe.”

Their equation, A=Nast*fbt, describes A as the product of Nast – the number of habitable planets in a given volume of the Universe – multiplied by fbt – the likelihood of a technological species arising on one of these planets.

The volume considered could be, for example, the entire Universe, or just our Galaxy.

“The universe is more than 13 billion years old,” said Sullivan. “That means that even if there have been a thousand civilizations in our own galaxy, if they live only as long as we have been around—roughly ten thousand years—then all of them are likely already extinct.

And others won’t evolve until we are long gone. For us to have much chance of success in finding another "contemporary" active technological civilization, on average they must last much longer than our present lifetime.”

“Given the vast distances between stars and the fixed speed of light we might never really be able to have a conversation with another civilization anyway,” said Frank. “If they were 20,000 light years away then every exchange would take 40,000 years to go back and forth.”

But, as Frank and Sullivan point out, even if there aren’t other civilizations in our galaxy to communicate with now, the new result still has a profound scientific and philosophical importance.

“From a fundamental perspective the question is ‘has it ever happened anywhere before?’” said Frank.

"Our result is the first time anyone has been able to set any empirical answer for that question and it is astonishingly likely that we are not the only time and place that an advance civilization has evolved.”

According to Frank and Sullivan their result has a practical application as well. As humanity faces its crisis in sustainability and climate change we can wonder if other civilization-building species on other planets have gone through a similar bottleneck and made it to the other side.

As Frank puts it “We don’t even know if it’s possible to have a high-tech civilization that lasts more than a few centuries.”

With Frank and Sullivan’s new result, scientists can begin using everything they know about planets and climate to begin modeling the interactions of an energy-intensive species with their home world knowing that a large sample of such cases has already existed in the cosmos.

“Our results imply that our evolution has not been unique and has probably happened many times before. The other cases are likely to include many energy intensive civilizations dealing with their feedbacks onto their planets as their civilizations grow.

That means we can begin exploring the problem using simulations to get a sense of what leads to long lived civilizations and what doesn’t.”

Source: https://exoplanets.nasa.gov/news/1350/are-we-alone-in-the-universe-revisiting-the-drake-equation/

Image below: This artist’s conception of a planetary lineup shows habitable zone planets with similarities to Earth: from left, Kepler-22b, Kepler-69c, Kepler-452b, Kepler-62f and Kepler-186f. Last in line is Earth itself. Credit: NASA/JPL-Caltech

What is an Exoplanet?

An exoplanet, or extrasolar planet, is a planet outside of our solar system that usually orbits another star in our galaxy.


https://www.youtube.com/watch?v=0ZOhJe_7GrE

Most of the exoplanets discovered so far are in a relatively small region of our galaxy, the Milky Way. ("Small" meaning within thousands of light-years of our solar system; one light-year equals 5.88 trillion miles, or 9.46 trillion kilometers.)

That is as far as current telescopes have been able to probe. We know from NASA’s Kepler Space Telescope that there are more planets than stars in the galaxy.

Although exoplanets are far – even the closest known exoplanet to Earth, Proxima Centauri b, is still about 4 light-years away – scientists have discovered creative ways to spot these seemingly tiny objects.

How do we find exoplanets?

There are five methods scientists commonly use to discover exoplanets.

The two main techniques are the transit and radial velocity methods.

When a planet passes directly between an observer and the star it orbits, it blocks some of that starlight. For a brief period of time, that star’s light actually gets dimmer.

It's a tiny change, but it's enough to clue astronomers in to the presence of an exoplanet around a distant star. This is known as the transit method.

Orbiting planets cause stars to wobble in space, changing the color of light astronomers see when observing a star.

Stars are affected by the gravitational tug of their orbiting planets and, when observed through a telescope, this affects the star's light spectrum. If the star moves in the direction of the observer it will appear to be shifted toward blue.

If it is moving away from the observer, it will shift toward the red. Observing this is known as the radial velocity method.

NASA’s exoplanet space telescopes
Thousands of exoplanets have been discovered and confirmed orbiting other stars.

The first evidence of exoplanets dates to 1917 when Van Maanen identified the first polluted white dwarf, however, the first confirmed detection of an exoplanet would not come until the 1990s.

The discovery of exoplanets grew exponentially in the years to follow with the launch of the Kepler Space Telescope.

The Kepler mission was specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone (also called the “Godilocks zone,” the area around a star where rocky planets could have liquid water on the surface) and determine the fraction of stars that might have such planets around them.

After the second of Kepler’s four gyroscope-like wheels failed in 2013, Kepler completed its prime mission that November and began its extended mission, K2.

The spacecraft was retired in 2018, but Kepler data are still being used to find exoplanets (more than 2,700 confirmed so far).

NASA’s Spitzer Space Telescope (2013-2020) was not designed to search for exoplanets, but its infrared instruments made it an excellent exoplanet explorer. It was used in the notable discovery of the TRAPPIST-1 system.

In 2018 the Transiting Exoplanet Survey Satellite (TESS) was launched as a successor to Kepler to discover exoplanets in orbit around the brightest dwarf stars, the most common star type in our galaxy.

Future space missions such as NASA’s James Webb Space Telescope and the Nancy Grace Roman Space Telescope hold great promise for what we can learn from exoplanets.

Through spectroscopy, reading light signatures for information, astronomers hope to learn more about planet atmospheres and the conditions of the planets themselves.

Confirmed vs. candidate
Fast facts
What is an exoplanet candidate?
An exoplanet candidate is a likely planet discovered by a telescope but has not yet been proven to actually exist.

It is possible for some candidates to turn out to be "false positives." A planet is considered "confirmed" once it is verified through additional observation using two other telescopes.

There are currently thousands of planet candidates awaiting confirmation. But time on telescopes is considered a precious resource and it takes a lot of computing time to find which targets to investigate.

This is one area where amateur scientists can work with NASA data to help refine targets and even discover exoplanets. Where computers might miss a single transit, humans can detect small brightness dips in data that might tell us there is a planet to be found.

How do we name exoplanets?

Exoplanet names can look long and complicated at first, especially when compared to names like Venus and Mars.

However, there is a logic behind their naming system that is important to how scientists catalog thousands of planets.

Astronomers differentiate between the alphanumeric "designations" and alphabetical "proper names." All stars and exoplanets have designations, but very few have proper names.

The first part of an exoplanet name is usually the telescope or survey that discovered it. The number is the order in which the star was cataloged by position.

The lowercase letter stands for the planet, in the order in which the planet was found. The first planet found is always named b, with ensuing planets named c, d, e, f and so on.

The star that the exoplanet orbits is usually the undeclared "A" of the system, which can be useful if the system contains many stars, which themselves may be designated B or C.

(Stars get capital letters; planets receive lowercase designations.)

If a bunch of exoplanets around the same star are found at once, the planet closest to its star is named b with more distant planets named c, d, e and so on.

An example of an exoplanet name is Kepler-16b, where "Kepler" is the name of the telescope that observed the system, 16 is the order in which the star was cataloged and "b" is the closest planet to the star.

If we were naming Earth as an exoplanet, it would be called Sun d (Sun is the name of our star, and Earth is the third planet, starting with b, Mercury).

https://exoplanets.nasa.gov/what-is-an-exoplanet/in-depth/

� View Planet Parade in December �

Observers from the Earth will have a chance to spot the planet parade at the beginning of December. Five planets will gather in one sky area:
� Venus (-4.7m)
� Saturn (0.9m)
� Jupiter (-1.8 )
� Neptun (7.7)
� Uranus (6.0)

The dwarf planet Ceres (6.9), a large asteroid Pallas (7.6), and the Moon (-11.4) will settle nearby.

The best time to observe them is December 12, 2021; look for the celestial objects right after sunset. Venus, Saturn, Jupiter, and the Moon will be visible to the naked eye. A pair of binoculars or a small telescope will help you to see the dimmer Neptune, Uranus, Ceres, and Pallas. �

* Although there is now an official scientific definition of the term “planet parade,” astronomers use it to denote an astronomical event that happens when Solar System planets line up in the same sky area as seen from the Earth.
Source: Star Walk

Technosignature from Proxima Centauri — and why astronomers rejected it

The forensic analysis of a potential signal from another civilization reveals how challenging the search for extraterrestrial intelligence is likely to become.

On 29 April 2019, the Parkes Radio Telescope in New South Wales, Australia, picked up an unusual signal while searching for signs of intelligent life elsewhere in the universe.

The telescope was observing Proxima Centauri, the nearest star to the sun and host to a number of exoplanets that are potentially habitable.

The search was part of a project called Breakthrough Listen, which is hunting for technosignatures from other civilizations.

These searches gather vast amounts of data. So the first task is to filter the interesting signals from the background.

In theory, a technosignature must have two important properties.

The first is that it must be confined to a narrowband of frequencies with high information content, just like radio broadcasts on Earth. No known natural process can produce signals like this.

The second is that the frequency of the signal must drift in a way that is consistent with the motion of an exoplanet relative to the Earth. The drift is the result of the relative accelerations which causes a slight Doppler shift.

So Sofia Sheikh at the University of California, Berkeley and colleagues created a filter that automatically separates signals with these properties from all the others the telescope picks up.

They found over 4 million of them.

Signal of interest



To help pick out false alarms, the telescope regularly switches from its target to point in other directions. That allowed Sheikh and co to discount any signals that continued in both periods. That left just 5160 hits.

The team further filtered out any signals in the range of known radio transmitters and any with a drift that corresponds to the motion of satellites.

That left a single unexplained event. The team describe it as a narrowband signal with characteristics broadly consistent with a technosignature, which appeared during a 2.5 hour period of observation but only when the telescope was pointing towards Proxima Centauri.

“The event does not lie within the frequency range of any known local radio-frequency interference, and has many characteristics consistent with a putative transmitter located in another stellar system,” say Sheikh and co.”

They called this signal of interest Breakthrough Listen Candidate 1 or BLC1 and it has been the subject of an extraordinary investigation.

Attributing a signal to an alien civilization is the hypothesis of last resort. Before that, every conventional explanation has to be explored and refuted.

So Sheikh and co undertook a remarkable investigation into the possibility of complex but conventional explanations.

They began by re-observing Proxima Centauri earlier this year, exactly two years after the first observation, to replicate as far as possible the initial observing conditions.

During these observations, they found no evidence of a signal similar to BLC1.

They then re-examined the possibility that a moving transmitter nearby could be the source—a car, train, helicopter, plane, balloon etc. Perhaps such a moving transmitter could reproduce the observed drift on BLC1.

The problem with this explanation is that BLC1 appeared for several hours. The team could find no reasonable trajectory that reproduced the drift for such a long period of time.

“It is extremely difficult to construct a continual motion path that could persist as exhibited by the measured signal, even by varying the speed along the route,” they concluded.

They came to a similar conclusion that satellites could not be the source. Low Earth Orbit satellites move too quickly to be observed over such a long period.

And geostationary satellites do not drift. Neither could have produced BLC1.

Then there are deep space probes in distant parts of the Solar System.

But the team were able to rule them out because none are in line with the telescope and Proxima Centauri and so could not be the source.

Next, the team looked for drifting signals, similar to BLC1, in data that had been originally rejected by their filtering algorithm. This required the researchers to visually inspect the data, looking for patterns similar to BLC1.

Amazingly, they found four examples of BLC1-like signals with a signal-to-noise ration so low that they had failed to reach the detection threshold of their algorithm.

They then looked for similar signals in the data gathered from other stars, some 7000 observations in total. Again, amazingly, they found 1 example of a signal similar to BLC1.

“All five of these 982 MHz signals from different days are fainter than BLC1; three of them conclusively appear in the off-sources, while two of them are inconclusive,” say Sheikh and co.

These five signals point to an alternative explanation—that BLC1 Is a complex form of radio interference that just happened to appear at the time the team were observing Proxima Centauri.

If this were true, thought the researchers, there ought to be other examples of similar patterns at other frequencies.

So again they went back to the original data and found 36 signals at other frequencies that looked like BLC1 but that had been filtered out by the search algorithm as obvious radio interference.

These signals had “strikingly similar morphology to blc1”.

Finally, the team looked for mirror images of the BLC1 signal—in other words signals with negative drift rates. Sure enough, they found 27 mirrored lookalikes.

All these appeared in data from observations when the telescope was pointing away from Proxima Centauri.

To determine the possible origin of these signals, the team looked at their common properties, whether they could be part of a harmonic sequence from a parent signal or had a more complex relationship.

Detective work

That’s when the origin became clear. They all appeared to be multiples of frequencies used in common clock oscillators.

That meant the signals were almost certainly generated by the interaction of ordinary digital electronic devices, probably from the radio frequency environment of the telescope facility itself.

In other words, the telescope was probably picking up its own radio frequency interference, albeit a complex and rare example of it.

The team have yet to identify the precise origin but say that should be possible with future studies.

That’s interesting work that reveals just how challenging the search of extraterrestrial technosignatures will be. BLC1 will contribute in its own way to future research.

As a result of this work, Sheikh and co have produced a checklist of steps that astronomers will have to work through whenever they find a signal of interest, to rule out the possibility of this kind of complex interference.

It also raises important questions about data storage. A feature part of this work was the ability to reanalyze data that had originally been discarded as noise.

That’s a significant amount of data that is hard to store. Just how much of this should be stored in future, in what format and for how long is up for debate.

But Sheikh and co have shown how important it can be: “Here we have learned that neglecting to consider the entire operable bandwidth of a receiver can have serious consequences.”

If humanity is to have confidence in future observations, the forensic analysis of BLC1 is likely to be foundational.

Source: https://astronomy.com/news/2021/12/technosignature-from-proxima-centauri--and-why-astronomers-rejected-it

The Webb Space Telescope Will Rewrite Cosmic History. If It Works.


https://www.youtube.com/watch?v=shPwW11MEHg


https://www.youtube.com/watch?v=qyWsJzbH0XI

Source: https://www.quantamagazine.org/why-nasas-james-webb-space-telescope-matters-so-much-20211203/

NASA's Webb telescope moved to meet its rocket

On Dec. 7, NASA's James Webb Space Telescope was transferred to the final assembly building at Europe's Spaceport in French Guiana to meet its Ariane 5 launch vehicle.

Stowed inside a special transport container and mobile clean room, Webb's vitals were meticulously monitored throughout the entire process of moving between buildings.

The Ariane 5 rocket Webb will ride to space was moved to the same building on Nov. 29. Here, adjustable platforms allow engineers to access the launch vehicle and its payload.

The next steps ahead are to safely lift Webb to an upper platform which has been prepared so that Webb can be connected to the Ariane 5's upper stage.

After being connected to the rocket, technicians will move forward to encapsulate Webb inside Ariane 5's specially adapted fairing.

In preparation for a Dec. 22 launch, ground teams have already successfully completed the delicate operation of loading the spacecraft with the propellant it will use to steer itself while in space.

Webb will be the largest, most powerful telescope ever launched into space.

As part of an international collaboration agreement, ESA (the European Space Agency) is providing the telescope's launch service. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission.

Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).

Source: https://phys.org/news/2021-12-james-webb-space-telescope-rocket.html