Hubble’s Jupiter And The Shrinking Great Red Spot 

The Unreasonable Effectiveness of Mathematics in  the Natural Sciences

Scholars have often expressed astonishment for how well mathematics works to describe our physical world. In 1960, Eugene Wigner published an article with the title above commenting that

…the mathematical formulation of the physicist’s often crude experience leads, in an uncanny number of cases, to an amazingly accurate description of a large class of phenomena.

Here are some others’ thoughts:

The most incomprehensible thing about the universe is that it is comprehensible.

— Albert Einstein

Physics is mathematical not because we know so much about the physical world, but because we know so little; it is only its mathematical properties that we can discover.

— Bertrand Russell

How can it be that mathematics, being after all a product of human thought which is independent of experience, is so admirably appropriate to the objects of reality?

— Albert Einstein

Our physical world doesn’t have just some mathematical properties, it has only mathematical properties.

— Max Tegmark

Physicists may have fallen prey to a false dichotomy between mathematics and physics. It’s common for theoretical physicists to speak of mathematics providing a quantitative language for describing physical reality… But maybe… math is more than just a description of reality. Maybe math is reality.

— Brian Greene

More info at  https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness_of_Mathematics_in_the_Natural_Sciences

my type of meme

Lunar Eclipse 2019

Image Credit: Zachary Wells

The Surprising Reason Why Neutron Stars Don’t All Collapse To Form Black Holes

“The measurements of the enormous pressure inside the proton, as well as the distribution of that pressure, show us what’s responsible for preventing the collapse of neutron stars. It’s the internal pressure inside each proton and neutron, arising from the strong force, that holds up neutron stars when white dwarfs have long given out. Determining exactly where that mass threshold is just got a great boost. Rather than solely relying on astrophysical observations, the experimental side of nuclear physics may provide the guidepost we need to theoretically understand where the limits of neutron stars actually lie.”

If you take a large, massive collection of matter and compress it down into a small space, it’s going to attempt to form a black hole. The only thing that can stop it is some sort of internal pressure that pushes back. For stars, that’s thermal, radiation pressure. For white dwarfs, that’s the quantum degeneracy pressure from the electrons. And for neutron stars, there’s quantum degeneracy pressure between the neutrons (or quarks) themselves. Only, if that last case were the only factor at play, neutron stars wouldn’t be able to get more massive than white dwarfs, and there’s strong evidence that they can reach almost twice the Chandrasekhar mass limit of 1.4 solar masses. Instead, there must be a big contribution from the internal pressure each the individual nucleon to resist collapse.

For the first time, we’ve measured that pressure distribution inside the proton, paving the way to understanding why massive neutron stars don’t all form black holes.

Saturn’s rings and our planet Earth and Moon in the same frame captured by nasa’s Cassini spacecraft 19 July. (source @nasa) *Out Pale Blue Dot*

Amazing views from the International Space Station (ISS)

What is a protostar?

The formation of stars begins with the collapse and fragmentation of molecular clouds into very dense clumps.  These clumps initially contain ~0.01 solar masses of material, but increase in mass as surrounding material is accumulated through accretion.  The temperature of the material also increases while the area over which it is spread decreases as gravitational contraction continues, forming a more stellar-like object in the process.  During this time, and up until hydrogen burning begins and it joins the main sequence, the object is known as a protostar.

This stage of stellar evolution may last for between 100,000 and 10 million years depending on the size of the star being formed. If the final result is a protostar with more than 0.08 solar masses, it will go on to begin hydrogen burning and will join the main sequence as a normal star.  For protostars with masses less than this, temperatures are not sufficient for hydrogen burning to begin and they become brown dwarf stars.

Protostars are enshrouded in gas and dust and are not detectable at visible wavelengths.  To study this very early stage of stellar evolution, astronomers must use infrared or microwave wavelengths.

Protostars are also known as Young Stellar Objects (YSOs).

M43 - Part of the same star-forming complex as the Great Orion Nebula (M42)

Pacific Ocean seen from Gemini 7

Credit: NASA