Conquer Club

Millions of people across parts of Mexico, Canada, and the United States watched the rare total solar eclipse on Monday. The path of totality, a tiny area where the Moon completely obscures the Sun, crossed across cities and sent the United States into a frenzy.
However, this year's total solar eclipse was unlike any eclipse we've witnessed in our lifetime – even in 2017. Unlike the 2017 eclipse, the 2024 eclipse was unique in several aspects, from its duration, and path of totality to the expected solar phenomena.

Here's what makes the 2024 eclipse different from the 2017 event.

2024 vs 2017 Eclipse: What was different?
Wider Path of Totality
During this year's eclipse, the moon was almost 8,000 miles closer to Earth than the 2017 event, so the path of totality was wider. The path of totality ranged from 108 to 122 miles wide on Monday compared to a 62 to 71-mile path of totality during the last total solar eclipse.

Dutch-born Christiaan Huygens is probably one of the most famous physicists you've never heard of. His work in the late 17th century straddled both the intangible and tangible realms of our Universe: the nature of light, and the mechanics of moving objects.

Among his many contributions, Huygens proposed a wave theory of light that would give rise to physical optics, which deals with the interference, diffraction, and polarization of light. He also invented the first pendulum clock; the most accurate timekeeper for almost 300 years, right through the Industrial Revolution.

Little has been made of the connections between these two seemingly disparate fields of optics and classical mechanics – until now.
A pair of physicists at the Stevens Institute of Technology in New Jersey have revisited Huygens' seminal work on pendulums, published in 1673, and used his 350-year-old mechanical theorem to uncover some new connections between some of the strangest, and most fundamental, properties of light.

"With this first study we've shown clearly that by applying mechanical concepts, it's possible to understand optical systems in an entirely new way," says physicist Xiaofeng Qian.

Qian and his colleague at the Stevens Institute, Misagh Izadi, considered two properties of light in their calculations: polarization and a form of correlation known as classical, or non-quantum, entanglement.

These two properties reflect the strange duality of light that permeates every pocket of our Universe. In a quantum sense, light – like all forms of matter – can be described as waves rippling through space, but also as discrete particles localized to a single point.

This isn't just a quantum phenomenon, however. In the classical world of cogs and springs and tick-tocking clocks, light waves rise and fall like physical ripples on an intangible ocean, with properties linked to their ever-shifting progress through space.

"We've known for over a century that light sometimes behaves like a wave, and sometimes like a particle, but reconciling those two frameworks has proven extremely difficult," said Qian.

"Our work doesn't solve that problem – but it does show that there are profound connections between wave and particle concepts not just at the quantum level, but at the level of classical light-waves and point-mass systems."

Most commonly considered a quantum phenomenon, entanglement simply describes correlations in the properties of objects. (...)

Qian and Izadi envisaged light as a mechanical system to which Huygens' parallel axis theorem could be applied, and found a "profound" connection: the degree of a light wave's polarization was directly related to the degree of a recently recognized property called vector-space entanglement.

Qian and Izadi's calculations suggest that as one rises, the other falls, enabling the level of entanglement to be inferred directly from the level of polarization, and vice versa.

"Ultimately, this research is helping to simplify the way we understand the world, by allowing us to recognize the intrinsic underlying connections between apparently unrelated physical laws," Qian says.

The study was published in Physical Review Research.

NASA predicts that the recurrent nova T Coronae Borealis will explode sometime in 2024 in a rare event that could be visible to the naked eye.

The star system is located 3,000 light years from Earth.

“Unfortunately, we don’t know the timing of this as well as we know the eclipse,” NASA Meteoroid Environment Office lead Bill Cooke said.

Supernova in NGC 3621 in Hydra. Supernova 2024ggi, discovered a month ago, quickly reached visual magnitude 12.0, stayed there for a couple weeks, and is now beginning to drift down slightly (12.3 as of May 2nd). See the AAVSO's table of recent observations for updates.

NGC 3621, glowing at 10th magnitude, is rather far south at declination –33°. But it crosses the meridian soon after dark. For charts See Bob King's Jupiter meets Uranus in twilight; Supernova erupts in nearby galaxy.


FRIDAY, MAY 3

■ After sunset, use binoculars or a wide-field telescope to try for one last look at Jupiter. It's just above the west-northwest horizon in bright twilight. (Everything else in that area will be completely invisible.) If you succeed, you will be among the few people on Earth to see the giant planet so close to the end of its 2023-24 apparition.

■ On the opposite side of the Sun, low in eastern dawn sky, Saturday morning May 4th finds the waning crescent Moon hangings between Saturn to its upper right and Mars to its left or lower left, as shown below.