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kottke.org posts about universe

The Universe is much bigger than it is old

posted by Jason Kottke   Oct 20, 2017

In a Twitter thread, author Oliver Morton compares the physical scale of the Universe with its age (from the perspective of humans).

If a human life is 70 years long, there has been room for 200 million lives since the big bang, but 200 million humans, end to end, would reach just a bit further than the moon. If you had started walking towards the centre of the galaxy on the day of the big bang (had there been days, you, paths & galaxies), you would have got about 20 parsecs by now: just 0.25% of the way.

Maybe walking pace is the wrong metric. A nerve impulse travels around 70 times faster than a person walks. But even at the speed of thought, the age of the universe is too small for something to have reached the centre of the galaxy.

The situation is even worse when you choose another reference object, like UY Scuti, the largest known star. The red hypergiant is nearly 1.5 billion miles across and, because of its size and position near the center of the galaxy, is probably around 13 billion years old, just a few hundred million years younger than the age of the Universe itself.

Even if you use light as a marker, the size of Universe remains unfathomably immense. Over the course of the Universe’s lifetime, a photon could have travelled 13.8 billion light-years, just 15% of the current estimate of the Universe’s diameter of 93 billion light-years. See also what are the physical limits of humanity?

Infographic of the fascinating timeline of the far future

posted by Jason Kottke   Aug 17, 2017

Timeline of The Far Future

Timeline of the far future is one of my favorite pages on Wikipedia. It details what might happen to humanity, human artifacts, the Earth, the solar system, and the Universe from 10,000 years from now until long past the heat death of the Universe. Information is Beautiful has made a lovely infographic of the timeline.

Reading through the timeline is a glorious way to spend time…here are a few favorites I noticed this time around as well as some from my first post.

August 20, 10,663: “A simultaneous total solar eclipse and transit of Mercury.”

20,000 years: “The Chernobyl Exclusion Zone, the 1,000 sq mi area of Ukraine and Belarus left deserted by the 1986 Chernobyl disaster, becomes safe for human life.”

296,000 years: “Voyager 2 passes within 4.3 light-years of Sirius, the brightest star in the night sky.”

1 million years: “Highest estimated time until the red supergiant star Betelgeuse explodes in a supernova. The explosion is expected to be easily visible in daylight.”

1 million years: “On the Moon, Neil Armstrong’s ‘one small step’ footprint at Tranquility Base will erode by this time, along with those left by all twelve Apollo moonwalkers, due to the accumulated effects of space weathering.”

15.7 million: “Half-life of iodine-129, the most durable long-lived fission product in uranium-derived nuclear waste.”

100 million years: “Future archaeologists should be able to identify an ‘Urban Stratum’ of fossilized great coastal cities, mostly through the remains of underground infrastructure such as building foundations and utility tunnels.”

1 billion years: “Estimated lifespan of the two Voyager Golden Records, before the information stored on them is rendered unrecoverable.”

4 billion years: “Median point by which the Andromeda Galaxy will have collided with the Milky Way, which will thereafter merge to form a galaxy dubbed ‘Milkomeda’.”

7.59 billion years: The Earth and Moon are very likely destroyed by falling into the Sun, just before the Sun reaches the tip of its red giant phase and its maximum radius of 256 times the present-day value. Before the final collision, the Moon possibly spirals below Earth’s Roche limit, breaking into a ring of debris, most of which falls to the Earth’s surface.

100 billion years: “The Universe’s expansion causes all galaxies beyond the Milky Way’s Local Group to disappear beyond the cosmic light horizon, removing them from the observable universe.”

Personal light cones

posted by Jason Kottke   Dec 02, 2008

When I was born 35.2 years ago, a light cone started expanding away from Earth out into the rest of the universe (Minkowski space-temporally speaking, of course). Thanks to updates from Matt Webb’s fancy RSS tool, I know that my personal light cone is about to envelop the Zeta Herculis binary star system, located 35.2 light years from Earth in the constellation Hercules.

With a mass some 50 percent greater than the Sun, however, and beginning its evolution toward gianthood (its core hydrogen fusion likely shut down), Zeta Her A is 6 times more luminous than the Sun with a radius 2.5 times as large. Nevertheless, the star gives a good idea of what the Sun would look like from a great distance, in Zeta Her’s case 35 light years. The companion (Zeta Her B), a cooler class G (G7) hydrogen-fusing dwarf with a luminosity only 65 percent that of the Sun and a mass about 85 percent solar, orbits with a period of 34.5 years at a mean distance of 15 Astronomical Units (over 50 percent farther than Saturn is from the Sun). A rather high eccentricity takes the two as far apart as 21 AU and as close as 8 AU.

Hercules is of course named for the Greek hero, Heracles. Next up is Delta Trianguli, another binary star system, in about two months.

Fractal universe

posted by Jason Kottke   Jun 26, 2008

Is the universe fractal-like, even on large scales? A group of Italian and Russian scientists argue that it displays a fractal pattern on a scale of 100 million light years. Other scientists aren’t so sure.

Many cosmologists find fault with their analysis, largely because a fractal matter distribution out to such huge scales undermines the standard model of cosmology. According to the accepted story of cosmic evolution, there simply hasn’t been enough time since the big bang nearly 14 billion years ago for gravity to build up such large structures.

Are there many small galaxies, like the

posted by Jason Kottke   Jun 06, 2007

Are there many small galaxies, like the one just discovered just outside our own, orbiting the larger visible galaxies?

Three trillion years from now, the universe

posted by Jason Kottke   May 31, 2007

Three trillion years from now, the universe will be observably static, the Milky Way alone, and scientists of the day likely won’t be able to “infer that the beginning involved a Big Bang”.

Happy birthday, universe

posted by Jason Kottke   Oct 23, 2006

According to the Ussher-Lightfoot Calendar, today is the 6,009th birthday of the universe. Based on James Ussher’s interpretation of the Bible, God created “the heaven and the earth” on October 23, 4004 BC. Happy birthday, everything!

Note: I’m doing Mr. Ussher’s precise chronology a disservice by fudging the Julian calendar date that he derived with the Gregorian calendar we now use. For that, I apologize.

Stephen Hawking and Thomas Hertog are publishing

posted by Jason Kottke   Jun 21, 2006

Stephen Hawking and Thomas Hertog are publishing a paper that argues that the universe “began in just about every way imaginable” simultaneously and then most of the possibilites withered away with the rest blending together to make the current universe.

Maybe the universe is a trillion years

posted by Jason Kottke   May 05, 2006

Maybe the universe is a trillion years old and has experienced several big bangs and big collapses over the years. “People have inferred that time began then, but there really wasn’t any reason for that inference. What we are proposing is very radical. It’s saying there was time before the big bang.”

Jim Holt asks Freeman Dyson, Lawrence Krauss,

posted by Jason Kottke   Oct 31, 2005

Jim Holt asks Freeman Dyson, Lawrence Krauss, Ed Witten and other in trying to figure out how the universe will end. Further reading: Time Without End by Freeman Dyson, Frank Tipler’s Omega Point theory, and The Physics of Extra-Terrestrial Civilizations by Michio Kaku.