Lifeboat Foundation

Astronomers have proposed a new way to solve the so-called “Hubble tension,” but the approach ultimately raises more questions than it answers.

By way of background, cosmologists are in a bit of a crisis these days. One of the most important numbers they can measure is the so-called Hubble constant, the rate of expansion of the present-day universe. At their disposal cosmologists have two sets of tools to measure this number. On one side are tools that probe the relatively nearby universe, like measuring the brightnesses of a certain kind of exploding star known as Type 1a supernovae. These supernovae all erupt with the same absolute brightness, so by measuring their observed magnitudes, astronomers can calculate their distances, and then use that to estimate how quickly the universe is expanding.

The downside of this approach is that supernovae don’t always explode with exactly the same brightness, and for the kind of precision measurements astronomers are aiming for, they have to include assumptions and modeling of supernovae, which can potentially introduce inaccuracies.

I’ve been diving into this cool concept called gravitational time dilation, and it’s like this mind-bending thing predicted by Albert Einstein in his theory of relativity. This concept highlights the actual difference in elapsed time between events observed by individuals situated at varying distances from a massive gravitational source.

If you’re hanging out close to a massive gravitational source, like a planet or star, time slows down for you. It’s like a cosmic slow-motion effect. But if you move away from it, time speeds up. This has been proven in experiments with atomic clocks placed at different heights — the closer to the Earth’s surface, the slower the clock ticks compared to those higher up.

Einstein first talked about this in 1907 when he was figuring out special relativity in speedy frames of reference. In general relativity, it’s like time is doing a dance based on where you are in space, as described by this thing called a metric tensor.

Natasha and Max also appear in a recent video titled “Transhumanism. What it is not” in conversation with David Wood and two representatives of the anti-transhumanist camp, Alexander Thomas and Émile Torres. I’m not familiar with the work of Thomas. I’m more familiar with the work of Torres. I very strongly disagree with most of what Torres says, but I must concede that Torres seems an intelligent and perceptive person, not without a certain endearing grace. However, BS is BS.

I’ve watched and listened again to the awesome conversation between Lex Fridman and Guillaume Verdon aka Beff Jezos, the founder of the movement called effective accelerationism (e/acc) and the company Extropic AI. This long conversation (almost 3 hours) touches a lot of things including physics, quantum, thermodynamics, Artificial Intelligence, LLMs, space, e/acc philosophy & metaphysics, and of course the meaning of life & all that. This is the most complete talk on e/acc so far and is likely to remain so for some time. Watch it all, and let’s accelerate the fuck away from mediocrity toward unlimited extropian and cosmist greatness.

Continue reading “Old and new futurisms in Silicon Valley” »

Today, the star-formation rate across the Universe is a mere trickle: just 3% of what it was at its peak. Here’s what it was like back then.

A recent study published in the Astrophysical Journal Letters investigates the potential existence of Mars-sized free-floating planets (FFPs)—also known as rogue planets, starless planets, and wandering planets—that could have been captured by our sun’s gravity long ago and orbit in the outer solar system approximately 1,400 astronomical units (AU) from the sun. For context, the farthest known planetary body in the solar system is Pluto, which orbits approximately 39 AU from the sun, and is also part of the Kuiper Belt, which scientists estimate extends as far out as 1,000 AU from the sun.

NASA’s Lunar Reconnaissance Orbiter (LRO) has successfully bounced a laser off of India’s Vikram lander, which successfully touched down on the Moon’s surface in August.

The LRO’s laser altimeter aimed its sights at Vikram in December, shooting it with a series of laser pulses. Vikram’s 2-inch-wide retroreflector, which comes courtesy of NASA, bounced these signals right back, with scientists confirming the first-of-its-kind “ping” moments later.

The feat could revolutionize the way we locate objects and determine their exact locations on the Moon’s surface from vast distances using a surprisingly low-tech solution.

It’s a lot to process.

A rapid reshaping of orbits resulting from a close encounter with Jupiter or Saturn can lead Centaurs to exhibit comet-like activity, according to a Planetary Science Institute Senior Scientist Eva Lilly paper.

Centaurs are small bodies similar to asteroids in size but to comets in composition that revolve around the sun in the outer solar system, mainly between the orbits of Jupiter and Neptune.

We have found some answers to the long-standing mystery of why some Centaurs became active like comets while the rest appear like regular quiet asteroids. Nobody knew why they behaved this way. It did not make any sense.

TOKYO (AP) — Japan became the fifth country in history to reach the moon when one of its spacecrafts without astronauts successfully made a soft landing on the lunar surface early Saturday.

However, space officials said they need more time to analyze whether the Smart Lander for Investigating Moon, or SLIM, achieved its mission priority of making a pinpoint landing. They also said the craft’s solar panel had failed to generate power, which could shorten its activity on the moon.

Space officials believe the SLIM’s small rovers were launched as planned and that data was being transmitted back to Earth, said Hitoshi Kuninaka, head of the Institute of Space and Astronautical Science, a unit of Japan’s space agency.