Tag: JWST

Searching for alien life

Another item about the James Webb Space Telescope (JWST).

I make no apologies for returning to the JWST in just a week after publishing my first article about the telescope. For I found the latest article, again published on The Conversation, to be incredible and that was all I needed to share it with you.

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To search for alien life, astronomers will look for clues in the atmospheres of distant planets – and the James Webb Space Telescope just proved it’s possible to do so

Published July 14th, 2022.

By Chris Impey University Distinguished Professor of Astronomy, University of Arizona and

Daniel Apai Professor of Astronomy and Planetary Sciences, University of Arizona.

The ingredients for life are spread throughout the universe. While Earth is the only known place in the universe with life, detecting life beyond Earth is a major goal of modern astronomy and planetary science.

We are two scientists who study exoplanets and astrobiology. Thanks in large part to next-generation telescopes like James Webb, researchers like us will soon be able to measure the chemical makeup of atmospheres of planets around other stars. The hope is that one or more of these planets will have a chemical signature of life.

There are many known exoplanets in habitable zones – orbits not too close to a star that the water boils off but not so far that the planet is frozen solid – as marked in green for both the solar system and Kepler-186 star system with its planets labeled b, c, d, e and f. NASA Ames/SETI Institute/JPL-Caltech/Wikimedia Commons

Habitable exoplanets

Life might exist in the solar system where there is liquid water – like the subsurface aquifers on Mars or in the oceans of Jupiter’s moon Europa. However, searching for life in these places is incredibly difficult, as they are hard to reach and detecting life would require sending a probe to return physical samples.

Many astronomers believe there’s a good chance that life exists on planets orbiting other stars, and it’s possible that’s where life will first be found.

Theoretical calculations suggest that there are around 300 million potentially habitable planets in the Milky Way galaxy alone and several habitable Earth-sized planets within only 30 light-years of Earth – essentially humanity’s galactic neighbors. So far, astronomers have discovered over 5,000 exoplanets, including hundreds of potentially habitable ones, using indirect methods that measure how a planet affects its nearby star. These measurements can give astronomers information on the mass and size of an exoplanet, but not much else.

Every material absorbs certain wavelengths of light, as shown in this diagram depicting the wavelengths of light absorbed most easily by different types of chlorophyll. Daniele Pugliesi/Wikimedia CommonsCC BY-SA

Looking for biosignatures

To detect life on a distant planet, astrobiologists will study starlight that has interacted with a planet’s surface or atmosphere. If the atmosphere or surface was transformed by life, the light may carry a clue, called a “biosignature.”

For the first half of its existence, Earth sported an atmosphere without oxygen, even though it hosted simple, single-celled life. Earth’s biosignature was very faint during this early era. That changed abruptly 2.4 billion years ago when a new family of algae evolved. The algae used a process of photosynthesis that produces free oxygen – oxygen that isn’t chemically bonded to any other element. From that time on, Earth’s oxygen-filled atmosphere has left a strong and easily detectable biosignature on light that passes through it.

When light bounces off the surface of a material or passes through a gas, certain wavelengths of the light are more likely to remain trapped in the gas or material’s surface than others. This selective trapping of wavelengths of light is why objects are different colors. Leaves are green because chlorophyll is particularly good at absorbing light in the red and blue wavelengths. As light hits a leaf, the red and blue wavelengths are absorbed, leaving mostly green light to bounce back into your eyes.

The pattern of missing light is determined by the specific composition of the material the light interacts with. Because of this, astronomers can learn something about the composition of an exoplanet’s atmosphere or surface by, in essence, measuring the specific color of light that comes from a planet.

This method can be used to recognize the presence of certain atmospheric gases that are associated with life – such as oxygen or methane – because these gasses leave very specific signatures in light. It could also be used to detect peculiar colors on the surface of a planet. On Earth, for example, the chlorophyll and other pigments plants and algae use for photosynthesis capture specific wavelengths of light. These pigments produce characteristic colors that can be detected by using a sensitive infrared camera. If you were to see this color reflecting off the surface of a distant planet, it would potentially signify the presence of chlorophyll.

Telescopes in space and on Earth

It takes an incredibly powerful telescope to detect these subtle changes to the light coming from a potentially habitable exoplanet. For now, the only telescope capable of such a feat is the new James Webb Space Telescope. As it began science operations in July 2022, James Webb took a reading of the spectrum of the gas giant exoplanet WASP-96b. The spectrum showed the presence of water and clouds, but a planet as large and hot as WASP-96b is unlikely to host life.

However, this early data shows that James Webb is capable of detecting faint chemical signatures in light coming from exoplanets. In the coming months, Webb is set to turn its mirrors toward TRAPPIST-1e, a potentially habitable Earth-sized planet a mere 39 light-years from Earth.

Webb can look for biosignatures by studying planets as they pass in front of their host stars and capturing starlight that filters through the planet’s atmosphere. But Webb was not designed to search for life, so the telescope is only able to scrutinize a few of the nearest potentially habitable worlds. It also can only detect changes to atmospheric levels of carbon dioxide, methane and water vapor. While certain combinations of these gasses may suggest life, Webb is not able to detect the presence of unbonded oxygen, which is the strongest signal for life.

Animals, including cows, produce methane, but so do many geologic processes. Jernej Furman/Wikimedia CommonsCC BY

Is it biology or geology?

Even using the most powerful telescopes of the coming decades, astrobiologists will only be able to detect strong biosignatures produced by worlds that have been completely transformed by life.

Unfortunately, most gases released by terrestrial life can also be produced by nonbiological processes – cows and volcanoes both release methane. Photosynthesis produces oxygen, but sunlight does, too, when it splits water molecules into oxygen and hydrogen. There is a good chance astronomers will detect some false positives when looking for distant life. To help rule out false positives, astronomers will need to understand a planet of interest well enough to understand whether its geologic or atmospheric processes could mimic a biosignature

The next generation of exoplanet studies has the potential to pass the bar of the extraordinary evidence needed to prove the existence of life. The first data release from the James Webb Space Telescope gives us a sense of the exciting progress that’s coming soon.

The James Webb Space Telescope is the first telescope able to detect chemical signatures from exoplanets, but it is limited in its capabilities. NASA/Wikimedia Commons

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So despite the advances in technology that resulted in the JWST it will still not be possible to detect unbonded oxygen; a sure indicator of life. It will be able to detect many other fascinating aspects of stars and planets beyond the Milky Way. I do not know if “The first data release…” relates to software or whether further launches of Mk 2 ‘JWST’ will be required. I will try and find out!

A heart-rending plea from George Monbiot

It is about global warming.

The article from George Monbiot came into my mailbox quite recently. Now of course Mr. Monbiot has a living to make and him publishing articles in the Guardian newspaper is normal. But I sensed that in this particular post he was worried. Worried about the situation regarding the planet and, by implication, all those who live on it.

I read yesterday on the UK Met Office blog about HILL events.

HILL events go beyond traditional weather extremes, potentially taking the climate system into uncharted territories. For example, much of the UK’s climate is predicated on two large elements of the climate system: the North Atlantic jet stream, a core of strong winds five to seven miles above the Earth’s surface, and the Atlantic Meridional Overturning Circulation (AMOC), a system of ocean currents which transports warm water northwards in the Atlantic.

Later on in that Met Office article it was said:

Prof Richard Betts MBE is the Head of Climate Impacts Research in the Met Office Hadley Centre and a Professor at the University of Exeter. Prof Betts, who led the team which prepared the Technical Report for the UK’s 3rd Climate Change Risk Assessment (CCRA3), is calling for a monitoring, attribution and prediction system that can provide early warning of HILLs. Professor Betts said: “With rising global temperatures, we are edging closer to the thresholds for more and more HILL events. Greater research into these events will help scientists advise policy makers on their thresholds and impacts.”

A week ago I wrote with real pride about the achievements of the James Webb Space Telescope (JWST). Later on I felt some shame that the focus on the real issue, that of climate change, was too low a priority for the US, let alone the world! Then I looked up the US expenditure on the military. Here’s a small quote from WikiPedia: “In May 2021, the President’s defense budget request for fiscal year 2022 (FY2022) is $715 billion, up $10 billion, from FY2021’s $705 billion.”[1] That puts the JWST into perspective. JWST cost ten billion dollars.

Expand one’s mind and just think of the global cost of war!

Here’s George Monbiot. Republished with his permission.

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Losing It

10th January, 2022

Faced with the gathering collapse of the biosphere, and governments’ refusal to take the necessary action, how do we stop ourselves from falling apart?

By George Monbiot, published in the Guardian 4th January 2022

No wonder journalists have slated it. They’ve produced a hundred excuses not to watch the climate breakdown satire Don’t Look Up: it’s “blunt”, it’s “shrill”, it’s “smug”. But they will not name the real problem: it’s about them. The movie is, in my view, a powerful demolition of the grotesque failures of public life. And the sector whose failures are most brutally exposed is the media.

While the film is fast and funny, for me, as for many environmental activists and climate scientists, it seemed all too real. I felt as if I were watching my adult life flash past me. As the scientists in the film, trying to draw attention to the approach of a planet-killing comet, bashed their heads against the Great Wall of Denial erected by the media and sought to reach politicians with 10-second attention spans, all the anger and frustration and desperation I’ve felt over the years boiled over.

Above all, when the scientist who had discovered the comet was pushed to the bottom of the schedule by fatuous celebrity gossip on a morning TV show and erupted in fury, I was reminded of my own mortifying loss of control on Good Morning Britain in November. It was soon after the Cop26 climate conference in Glasgow, where we had seen the least serious of all governments (the UK was hosting the talks) failing to rise to the most serious of all issues. I tried, for the thousandth time, to explain what we are facing, and suddenly couldn’t hold it in any longer. I burst into tears on live TV.

I still feel deeply embarrassed about it. The response on social media, like the response to the scientist in the film, was vituperative and vicious. I was faking. I was hysterical. I was mentally ill. But, knowing where we are and what we face, seeing the indifference of those who wield power, seeing how our existential crisis has been marginalised in favour of trivia and frivolity, I now realise that there would be something wrong with me if I hadn’t lost it.

In fighting any great harm, in any age, we find ourselves confronting the same forces: distraction, denial and delusion. Those seeking to sound the alarm about the gathering collapse of our life-support systems soon hit the barrier that stands between us and the people we are trying to reach, a barrier called the media. With a few notable exceptions, the sector that should facilitate communication thwarts it.

It’s not just its individual stupidities that have become inexcusable, such as the platforms repeatedly given to climate deniers. It is the structural stupidity to which the media are committed. It’s the anti-intellectualism, the hostility to new ideas and aversion to complexity. It’s the absence of moral seriousness. It’s the vacuous gossip about celebrities and consumables that takes precedence over the survival of life on Earth. It’s the obsession with generating noise, regardless of signal. It’s the reflexive alignment with the status quo, whatever it may be. It’s the endless promotion of the views of the most selfish, odious and antisocial people, and the exclusion of those who are trying to defend us from catastrophe, on the grounds that they are “worthy”, “extreme” or “mad” (I hear from friends in the BBC that these terms are still used there to describe environmental activists).

Even when these merchants of distraction do address the issue, they tend to shut out the experts and interview actors, singers and other celebs instead. The media’s obsession with actors vindicates Guy Debord’s predictions in his book The Society of the Spectacle, published in 1967. Substance is replaced by semblance, as even the most serious issues must now be articulated by people whose work involves adopting someone else’s persona and speaking someone else’s words. Then the same media, having turned them into spokespeople, attack these actors as hypocrites for leading a profligate lifestyle.

Similarly, it’s not just the individual failures by governments at Glasgow and elsewhere that have become inexcusable, but the entire framework of negotiations. As crucial Earth systems might be approaching their tipping point, governments still propose to address the issue with tiny increments of action, across decades. It’s as if, in 2008, when Lehman Brothers collapsed and the global financial system began to sway, governments had announced that they would bail out the banks at the rate of a few million pounds a day between then and 2050. The system would have collapsed 40 years before their programme was complete. Our central, civilisational question, I believe, is this: why do nations scramble to rescue the banks but not the planet?

So, as we race towards Earth system collapse, trying to raise the alarm feels like being trapped behind a thick plate of glass. People can see our mouths opening and closing, but they struggle to hear what we are saying. As we frantically bang the glass, we look ever crazier. And feel it. The situation is genuinely maddening. I’ve been working on these issues since I was 22, and full of confidence and hope. I’m about to turn 59, and the confidence is turning to cold fear, the hope to horror. As manufactured indifference ensures that we remain unheard, it becomes ever harder to know how to hold it together. I cry most days now.

http://www.monbiot.com

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Now there is very little that we folk can do. We can do our best but it all comes to nought. The real change is for governments, especially the governments of the US, China, Russia, the UK, and Europe, to make a difference soon.

Don’t hold your breath!