Author: Aeon Magazine

This article was originally published at Aeon and has been republished under Creative Commons.

Categories
Astrobiology Evolution

Proof of life: how would we recognize an alien if we saw one?

An octomite
An 'octomite', or a speculative alien produced by natural selection. Courtesy Helen Cooper/Cambridge University The researchers imagine a complex alien called the ‘Octomite’ which is comprised of a hierarchy of entities, where each lower level collection of entities has aligned evolutionary interests such that conflict is effectively eliminated. These entities engage in division of labour, with various parts specialising on various tasks, such that the parts are mutually dependent.

What would convince you that aliens existed? The question came up recently at a conference on astrobiology, held at Stanford University in California. Several ideas were tossed around – unusual gases in a planet’s atmosphere, strange heat gradients on its surface. But none felt persuasive. Finally, one scientist offered the solution: a photograph. There was some laughter and a murmur of approval from the audience of researchers: yes, a photo of an alien would be convincing evidence, the holy grail of proof that we’re not alone.

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Categories
Global Warming Climate Planet Earth

We are heading for a New Cretaceous, not for a new normal

Arctic melting
Credit: NASA photograph by Kathryn Hansen. Caption by Mike Carlowicz. If you have never been north of the Arctic Circle, it is easy to imagine that the “ice cap” at the top of the world is a uniform sheet of white. The reality, particularly during the spring and summer melt, is a mottled landscape of white, teal, slate gray, green, and navy. The sea ice atop the Arctic Ocean can—as shown in this photograph from July 12, 2011—look more like swiss cheese or a bright coastal wetland. As ice melts, the liquid water collects in depressions on the surface and deepens them, forming melt ponds. These fresh water ponds are separated from the salty sea below and around it, until breaks in the ice merge the two. Researchers on the NASA-funded ICESCAPE mission -Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment-have been examining melt ponds, the ice around them, and the waters below for three weeks, with three more to go. Carried by the U.S. Coast Guard Cutter Healy, a team of oceanographers, marine biologists, and glaciologists are investigating how changing conditions in the Arctic affect the ocean’s chemical and biological makeup. The science team collects water samples to examine water chemistry and to observe the colonies of plankton growing in the water and on the surfaces of the ice. Other instruments are used to assess how much and how far sunlight is penetrating into—and warming—the Arctic Ocean. Still others are measuring the current systems that move water from the depths to the surface, as well as horizontally across the Beaufort and Chukchi Seas. Incidentally, the crew members in the photo are not harvesting data; they are collecting supplies. A C-130 airplane flew by earlier in the day, dropping a parachuted canister of hardware for fixing instruments and other machinery on the icebreaker. NASA science writer Kathryn Hansen is blogging daily from the ICESCAPE cruise.

A lazy buzz phrase – ‘Is this the new normal?’ – has been doing the rounds as extreme climate events have been piling up over the past year. To which the riposte should be: it’s worse than that – we’re on the road to even more frequent, more extreme events than we saw this year.

We have known since the 1980s what’s in store for us. Action taken then to reduce emissions by 20 per cent by 2005 might have restricted the global temperature rise to less than 1.5 degrees Celsius. But nothing was done, and the welter of climate data mounting since then only confirms and refines the original predictions. So where are we now?

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Categories
Life on Earth Evolution

There are more microbial species on Earth than stars in the galaxy

Dwindling Diatoms
Earth's oceans teem with microscopic plants called phytoplankton. But according to a new NASA study, populations of diatoms, the largest type of phytoplankton algae, have declined more than 1 percent per year from 1998 to 2012. Phytoplankton are an essential base of the marine food web and absorb carbon dioxide dissolved in the ocean that originally came from the atmosphere. The tiny organisms occupy the uppermost layer of ocean water, called the mixed layer, where waves and currents continually churn, drawing up nutrients from a deeper layer of water below. Scientists say the phytoplankton declines observed over the 15-year study period are due to the mixed layer becoming shallower, which results in fewer nutrients reaching the diatoms. The reduction in population may reduce the amount of carbon dioxide drawn out of the atmosphere and transferred to the deep ocean for long-term storage. Image and text: NASA

For centuries, humans have endeavoured to discover and describe the sum of Earth’s biological diversity. Scientists and naturalists have catalogued species from all continents and oceans, from the depths of Earth’s crust to the highest mountains, and from the most remote jungles to our most populated cities. This grand effort sheds light on the forms and behaviours that evolution has made possible, while serving as the foundation for understanding the common descent of life. Until recently, our planet was thought to be inhabited by nearly 10 million species (107). Though no small number, this estimate is based almost solely on species that can be seen with the naked eye.

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Categories
Space Exploration

How far beyond Earth will we go to safeguard our species?

Bruce McCandless II performs the first untethered spacewalk on February 7, 1984
NASA astronaut Bruce McCandless during the first untethered spacewalk in history. In this photograph taken on February 7, 1984 by his fellow crewmembers aboard the Earth-orbiting Space Shuttle Challenger on the STS-41B mission, McCandless II approaches his maximum distance (98 meters/320 feet) from the vehicle. McCandless became the first astronaut to maneuver about in space untethered, during this first "field" tryout of a nitrogen-propelled, hand-controlled backpack device called the Manned Maneuvering Unit (MMU). Not long afterward, NASA discontinued such actions and decided to perform only tethered spacewalks for safety reasons. In 1994, NASA unveiled a new backpack called Simplified Aid for EVA Rescue, or Safer, and tested it with an untethered spacewalk, the fourth, and thus far last untethered extra-vehicular activity it has performed. Every astronaut at the International Space Station wears Safer, which is smaller and lighter than the manned maneuvering units, for use during an emergency. You can see this image with max. resolution on NASA.gov

The human future in the cosmos could be all but limitless if we don’t destroy ourselves first. The same would be true of intelligent aliens elsewhere in the Universe, assuming they exist: how far they travel depends strongly on how long they survive as a species. That survival variable, which the US astronomer Frank Drake incorporated into his famous equation on the likelihood of technological civilizations beyond Earth, is unknowable at present because we are the only such civilization yet identified.

Let’s be optimistic and assume that humans are persistent, working their way through the manifest problems of mastering their tools – or at least mastering them long enough to plant colonies off-world so that our destruction in one place doesn’t mean the death of the species.

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Categories
Space Exploration Mars Scientific method

Why it’s only science that can answer all the big questions

Mars Sunset. April-15, 2015
NASA's Curiosity Mars rover recorded this view of the sun setting at the close of the mission's 956th Martian day, or sol (April 15, 2015), from the rover's location in Gale Crater. This was the first sunset observed in color by Curiosity. The image comes from the left-eye camera of the rover's Mast Camera (Mastcam). The color has been calibrated and white-balanced to remove camera artifacts. Mastcam sees color very similarly to what human eyes see, although it is actually a little less sensitive to blue than people are. Dust in the Martian atmosphere has fine particles that permit blue light to penetrate the atmosphere more efficiently than longer-wavelength colors. That causes the blue colors in the mixed light coming from the sun to stay closer to sun's part of the sky, compared to the wider scattering of yellow and red colors. The effect is most pronounced near sunset, when light from the sun passes through a longer path in the atmosphere than it does at mid-day. Malin Space Science Systems, San Diego, built and operates the rover's Mastcam. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover. This is a cropped image. You can see the full-size image on NASA Jet Propulsion Laboratory website.

Science has proved itself to be a reliable way to approach all kinds of questions about the physical world. As a scientist, I am led to wonder whether its ability to provide understanding is unlimited. Can it in fact answer all the great questions, the ‘big questions of being’, that occur to us?

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Categories
Climate Animals Environment Life on Earth

We have an ethical obligation to relieve individual animal suffering

A starving polar bear in the Arctic
A starving polar bear in the Arctic. Photo courtesy Wikipedia Arctic sea ice is one of the most endangered ecosystems on earth. ... The drastic loss of sea ice has led the U.S. government to list polar bears as a threatened species under the Endangered Species Act and to designate 187,000 square miles of polar bear “critical habitat” in Arctic sea ice and coastal areas. Text source: "The Disappearing Sea-ice Habitat of the Arctic" on endangered.org

Last winter, unforgettable video footage online showed a starving polar bear, struggling in its Arctic hunting grounds. Because of global warming, the ice was thin and the food supply was scarce. The video generated a wellspring of sympathy for the plight of this poor creature, and invigorated calls for stronger efforts to combat climate change – and rightly so.

Such advocacy on behalf of wildlife usually focuses on species and the effects of human-caused climate change on their survival and wellbeing as the ecosystems on which they depend undergo drastic changes. Thus, we should act to save the polar bear – that is, the polar bear species – by doing what we can to preserve its natural ecosystem. I am fully behind this kind of advocacy. Anybody who cares about the future of our planet and its occupants should be.

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Categories
Environment

The marvel of LED lighting is now a global blight to health

City Lights
Light pollution is often characterised as a soft issue in environmentalism. This perception needs to change. The inappropriate or excessive use of artificial light – known as light pollution – can have serious environmental consequences for humans, wildlife, and our climate. Light pollution is a side-effect of industrial civilization. Its sources include building exterior and interior lighting, advertising, outdoor area lighting (e.g. car parks/parking lots), offices, factories, streetlights, and illuminated sporting venues. It is most severe in highly industrialized, densely populated areas of North America, Europe, and Japan and in major cities in the Middle East and North Africa like Tehran and Cairo, but even relatively small amounts of light can be noticed and create problems. Image: Wikimedia

Light pollution is often characterised as a soft issue in environmentalism. This perception needs to change. Light at night constitutes a massive assault on the ecology of the planet, including us. It also has indirect impacts because, while 20 per cent of electricity is used for lighting worldwide, at least 30 per cent of that light is wasted. Wasted light serves no purpose at all, and excessive lighting is too often used beyond what is needed for driving, or shopping, or Friday-night football.

The electric light bulb is touted as one of the most significant technological advancements of human beings. It ranks right up there with the wheel, control of fire, antibiotics and dynamite. But as with any new and spectacular technology, there are invariably unintended consequences. With electric light has come an obliteration of night in much of the modern world; both outside in the city, and indoors during what was once ‘night’ according to the natural position of the Sun.

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Categories
Life on Earth

Extinction is forever: de-extinction can’t save what we had

Landscape with Birds by Roelant Savery, 1628
Landscape with Birds, (showing a dodo in the lower right corner) by Roelant Savery, 1628. Image Courtesy Wikimedia Roelant Savery (or Roeland(t) Maertensz Saverij, or de Savery, or many variants) (1576 - buried 25 February 1639), was a Flanders-born Dutch Golden Age painter. He primarily painted landscapes, often embellished with many meticulously painted animals and plants, regularly with a mythological or biblical theme as background. Among his best-known works are several depictions of the now-extinct dodo painted between 1611 and 1628.

When I hike up into the hills around Salt Lake City, above the Bonneville Shoreline Trail where the sagebrush gives way to the shade of the forest, mastodons are on my mind. Immense bones pulled from a sinkhole on the nearby Wasatch Plateau placed Mammut americanum in the area about 7,500 years ago – practically yesterday from the perspective of Deep Time. It might sound strange to say that I miss creatures I wasn’t around to see in the first place. But still, I mourn their loss as I plod through the woods, imagining their low rumbles and the splintering crashes as they browsed among the trees.

A small but growing number of scientists say that they could reverse that loss through de-extinction – genetic resuscitation in the style of the sci-fi yarn Jurassic Park. The idea is also now being marketed as conservation’s great hope to forestall the loss of biodiversity caused by humans. Biological Xeroxing was held up as one of the possibilities for species resuscitation at a National Geographic TEDx event on de-extinction in 2013. That same year, the discovery of a particularly juicy mammoth carcass, dripping with what appeared to be blood, sparked a flurry of reports assuring readers that the return of the mammoth is nigh. For if there’s blood, there’s DNA, and if there’s DNA, then we can have the Ice Age beast back, right?

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Categories
Environment People

The Earth’s carrying capacity for human life is not fixed

Crowded Istiklal street, Istanbul
Photo: "People walking on Istiklal Street in Istanbul" on Deposit Photos.

In a recent Nature Sustainability paper, a team of scientists concluded that the Earth can sustain, at most, only 7 billion people at subsistence levels of consumption (and this June saw us at 7.6 billion). Achieving ‘high life satisfaction’ for everyone, however, would transgress the Earth’s biophysical boundaries, leading to ecological collapse.

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