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How Deadly Would Extraterrestrial Bacteria Be to Humans?

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How deadly would a bacterium be to humans if it was brought from a completely different star system?

Drew Smith:

The chance that extraterrestrial bacteria would be deadly to humans is zero. Not just very, very small. Zero.

Pathogenesis requires intimacy. This intimacy is attained through millions of years of co-evolution. The need for intimacy is apparent when you look at how bacteria and viruses cause infections and disease.

Infection requires binding to a cell surface. Bacteria (and viruses) bind to human cells through proteins that recognize human proteins and carbohydrates. The structure of these human proteins and carbohydrates is, to a first approximation, arbitrary. There are an almost infinite number of permutations of them that could exist and work just fine. But only one does exist. The chance that an alien bacteria would have evolved to stick to that protein is infinitesimally small.

Even if this alien bacterium were able to stick to a cell surface, this alone would not establish an infection. Infecting bacteria secrete all kinds of toxins and virulence factors. These toxins and factors bind to specific human proteins. They block or modify their activity in ways that degrade cells and tissues, releasing nutrients that the bacteria can feed upon.

Again, the target proteins have fairly arbitrary structures. They are the result of billions of years of evolutionary history and their precise structure—and even their existence is not at all predictable. The chance that an alien bacterium would have evolved toxins that precisely target them is infinitesimally small.

Pathogenicity is extremely rare on Earth. There are millions, perhaps billions, of species of bacteria. The number of potential human pathogens among them is very small, no more than a couple hundred. And only a couple dozen are able to infect otherwise healthy humans. These are bacteria that have been with us for millions of years, evolving as we evolve, becoming intimately familiar with our proteins, our cells, our immune systems.

This knowledge is stamped into their genomes; it is a diary of their long association with us. It is not a book that could be written in an alien language. Alien bacteria are no more likely to be human pathogens than intelligent aliens are likely to speak Urdu as their native tongue. It just isn’t possible.

This post originally appeared on Quora. Click here to view.

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Frederick M. Brown, Getty Images
Stephen Hawking’s Memorial Will Beam His Words Toward the Nearest Black Hole
Frederick M. Brown, Getty Images
Frederick M. Brown, Getty Images

An upcoming memorial for Stephen Hawking is going to be out of this world. The late physicist’s words, set to music, will be broadcast by satellite toward the nearest black hole during a June 15 service in the UK, the BBC reports.

During his lifetime, Hawking signed up to travel to space on Richard Branson’s Virgin Galactic spaceship, but he died before he ever got the chance. (He passed away in March.) Hawking’s daughter Lucy told the BBC that the memorial's musical tribute is a “beautiful and symbolic gesture that creates a link between our father's presence on this planet, his wish to go into space, and his explorations of the universe in his mind.” She described it as "a message of peace and hope, about unity and the need for us to live together in harmony on this planet."

Titled “The Stephen Hawking Tribute,” the music was written by Greek composer Vangelis, who created the scores for Blade Runner and Chariots of Fire. It will play while Hawking’s ashes are interred at Westminster Abbey, near where Isaac Newton and Charles Darwin are buried, according to Cambridge News. After the service, the piece will be beamed into space from the European Space Agency’s Cebreros Station in Spain. The target is a black hole called 1A 0620-00, “which lives in a binary system with a fairly ordinary orange dwarf star,” according to Lucy Hawking.

Hawking wasn't the first person to predict the existence of black holes (Albert Einstein's general theory of relativity accounted for them back in the early 1900s), but he spoke at length about them throughout his career and devised mathematical theorems that gave credence to their existence in the universe.

Actor Benedict Cumberbatch, a friend of the Hawking family who portrayed the late scientist in the BBC film Hawking, will speak at the service. In addition to Hawking's close friends and family, British astronaut Tim Peake and several local students with disabilities have also been invited to attend.

[h/t BBC]

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IKEA
IKEA's New Collection for Tiny Apartments Is Inspired by Life on Mars
IKEA
IKEA

Living in a city apartment can feel claustrophobic at times. As Co.Design reports, the Swedish furniture brand IKEA took this experience to the extreme when designers visited a simulated Mars habitat as research for their latest line of housewares aimed at urbanites.

The new collection, called Rumtid, is tailored to fit the cramped spaces that many people are forced to settle for when apartment-hunting in dense, expensive cities. The designers knew they wanted to prioritize efficiency and functionality with their new project, and Mars research provided the perfect inspiration.

At the Mars Society's Mars Desert Research Station in Utah, scientists are figuring out how to meet the needs of potential Mars astronauts with very limited resources. Materials have to be light, so that they require as little rocket fuel as possible to ferry them to the red planet, and should ideally run on renewable energy.

IKEA's designers aren't facing quite as many challenges, but spending a few days at the simulated Martian habitat in Utah got them thinking on the right track. The team also conducted additional research at the famously snug capsule hotels in Tokyo. The Rumtid products they came up with include an indoor terrarium shaped like a space-age rocket, a set of colorful, compact air purifiers, and light-weight joints and bars that can be snapped into modular furniture.

The collection isn't ready to hit IKEA shelves just yet—the chain plans to make Rumtid available for customers by 2020. In the meantime, the designers hope to experiment with additional science fiction-worthy ideas, including curtains that clean the air around them.

Air purifiers designed for urban living.

Furniture joints on bubble wrap on black table.

Modular furniture holding water bag.

[h/t Co.Design]

All images courtesy of IKEA.

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