Showing all posts tagged: science

Space bubbles a Dyson sphere like solution to global warming?

15 June 2022

Dyson spheres are hypothetical mega-structures highly advanced planetary civilisations might construct around their host star to harness as much solar energy as possible to power their needs. Seen from a distance, a Dyson sphere would look like a massive shell almost completely encompassing a star.

It’d be like constructing a giant display case for the Sun. Needless to say building a Dyson sphere is no small undertaking, and would require an enormous quantity of resources, technological smarts, plus an unprecedented level of international cooperation. A single superpower could not take on an engineering feat of this scale alone, it’d be a team effort.

Dyson spheres have been in the news relatively recently. Fluctuations in the light of Tabby’s Star, located about 1,470 light-years from Earth, were puzzling astronomers, and the existence of a Dyson sphere was advanced as a possible explanation, though later ruled out.

While Dyson spheres, something late British American mathematician and physicist Freeman Dyson first wrote about in 1960, are unlikely to feature in our future anytime soon, the concept may help us combat global warming.

A team of MIT scientists have devised a solar filter of sorts, they call space bubbles. In short, a small structure made up of numerous of these space bubbles could be used to form a shield, deflecting a small, though sufficient amount of solar radiation away from the Earth.

The MIT scientists propose placing the space bubbles at the Lagrange point between the Earth and the Sun. Put simply, a Legrange point, is an area between two celestial objects, say the Earth and the Sun, where the gravity of both objects balance each other. For example if a satellite were placed at this Legrange point, it would stay put, and wouldn’t fall towards either the Earth or Sun.

Once in place, the space bubbles would act like an eclipsing body, in this case permanently blocking, or more like filtering, a small amount of the Sun’s rays reaching the Earth. While the proportion of solar radiation “blocked” would be minuscule, the MIT team say if just under two percent of “incident solar radiation” was deflected, current global warming could be fully reversed.

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In ten billion years the universe will double in size

28 May 2022

The Hubble constant expresses the rate at which the universe is expanding. The problem is though, no one has been able to nail down a precise value for the constant. That is, until now.

When the Hubble Space Telescope was launched in 1990 the universe’s expansion rate was so uncertain that its age might only be 8 billion years or as great as 20 billion years. After 30 years of meticulous work using the Hubble telescope’s extraordinary observing power, numerous teams of astronomers have narrowed the expansion rate to a precision of just over 1%. This can be used to predict that the universe will double in size in 10 billion years.

That’s mind blowing. To say the least. The already enormous cosmos will one day be twice its present size. Too bad no one here today will be around to see it. But what does it matter anyway? Well, you’d be surprised. Given some two point two million new books are published every year, one can only imagine how many more publications there’ll be in ten billion years’ time.

With a much larger universe by then, it’s comforting to know there will be space to put them somewhere…

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Time’s absence may make the universe easier to understand

19 April 2022

Writer’s on a tight deadline might disagree, but some physicists are beginning to believe that time may not exist. It’s a heady concept that there’s no such thing as lunch at one o’clock, because there’s no such thing as time, but when scientists talk about time, it’s on a cosmic scale, not a human one, says Dr Sam Baron of the Australian Catholic University, writing for The Conversation.

In the 1980s and 1990s, many physicists became dissatisfied with string theory and came up with a range of new mathematical approaches to quantum gravity. One of the most prominent of these is loop quantum gravity, which proposes that the fabric of space and time is made of a network of extremely small discrete chunks, or “loops”. One of the remarkable aspects of loop quantum gravity is that it appears to eliminate time entirely. Loop quantum gravity is not alone in abolishing time: a number of other approaches also seem to remove time as a fundamental aspect of reality.

The absence of time in this context though may account for discrepancies in some of the theories that scientists use to understand the universe, such as general relativity, quantum mechanics, and string theory.

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How the rings of Saturn were formed

23 March 2022

From BBC Earth Lab. Many millions of years ago, one of Saturn’s erstwhile moons, strayed a little too close, crossed a line, the Roche Limit, and shattered into billions of pieces, having been torn apart by the immense gravity of the Solar System’s second largest planet.

Saturn’s incredible ring system was the result of this cataclysmic event, once the remnants of the moon, some seventeen trillion tons of icy material, spread out in orbit around the planet. It would have been an incredible spectacle to witness, had anyone been around to see it all happen.

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Not the centre of the Earth that Jules Verne saw

10 February 2022

The long held notion that the centre, or core, of our planet consists of solid iron, may have been up-ended by a recent study suggesting Earth’s inner core is made up of a solid iron sublattice and liquid-like light elements:

A joint research team led by Prof. HE Yu from the Institute of Geochemistry of the Chinese Academy of Sciences (IGCAS) has found that the inner core of the Earth is not a normal solid but is composed of a solid iron sublattice and liquid-like light elements, which is also known as a superionic state. The liquid-like light elements are highly diffusive in iron sublattices under inner core conditions.

Well that differs somewhat from nineteenth century French author Jules Verne’s depiction, in his 1864 novel Journey to the Center of the Earth.

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