Very saddened to her that Jane Goodall, eminent primatologist who chronicled the lives of Chimps, passed away at 91. I had the honor of meeting her this year.

Each of the thousands of spots in this ESO image represents a distant star, and the glittering blue holes reveal glimpses of our neighboring galaxies, the Large and Small Magellanic Clouds.

Today Oct 1. On this date in 1990 physicist John Stewart Bell passed away. The originator of Bell's theorem in quantum physics regarding hidden-variable theories. In 2022, the Nobel Prize in Physics was awarded for work on Bell inequalities and experimental validation of Bell's theorem.

Today Sept 30. On this date in 1870 physicist Jean Perrin was born. In his studies of Brownian motion of minute particles suspended in liquids he verified Einstein's explanation of this phenomenon and thereby confirmed the atomic nature of matter. Awarded the Nobel Prize in Physics in 1926.

The Dumbbell Nebula ­in this ESO image— also known as Messier 27 or NGC 6853 — is a typical planetary nebula. The distance is rather uncertain, but is believed to be around 1,200 light-years.

Today Sept 29. On this date in 1901 physicist Enrico Fermi was born. One of very few physicists to excel in both theoretical & experimental physics. Awarded the 1938 Nobel Prize in Physics for work on induced radioactivity by neutron bombardment and for discovery of transuranium elements.

Today is Sept 28. 28 is the second "perfect" number (after 6), it is the sum of its proper divisors 28=1+2+4+7+14. It is also a "happy" number, when you repeatedly sum the squares of its digits, the sequence eventually leads to 1 : 2² + 8² = 68, 6² + 8² = 100, 1² + 0² + 0² = 1.

Today Sept 28. On this date in 1895 chemist Louis Pasteur passed away. Renowned for discoveries of the principles of vaccination, microbial fermentation, and pasteurization. His research led to remarkable breakthroughs in the understanding of the causes and preventions of diseases.

Another Hubble image of the Lagoon Nebula, an object with a deceptively tranquil name. The region is filled with intense winds from hot stars, churning funnels of gas, and energetic star formation, all embedded within an intricate haze of gas and pitch-dark dust.

Today Sept 27, 2025. It marks a special mathematical date because the numerals of the date form perfect squares. Written as 09/27/2025, it becomes 9,272,025, which is the square of 3,045. When written in the European format 27/09/2025, it becomes 27,092,025, the square of 5,205.

My book (with Jack Szostak) "Is Earth Exceptional?" now appeared also in Italian, Portuguese, Spanish, and Russian. Here are some of the covers:

An image of two spiral galaxies within the Virgo cluster of galaxies. The image was taken by the Vera Rubin Observatory.

Today is Sept 26. On this date in 1868 mathematician August Möbius passed away. He is best known for his work in analytic geometry and in topology. In the latter field he is especially remembered as one of the discoverers of the Möbius strip.

A beautiful ESO image of the nebula LHA 120-N 44 surrounding the star cluster NGC 1929. Lying within the Large Magellanic Cloud, this region of star formation features a superbubble of material expanding outwards due to the influence of the cluster of young stars at its heart.

Today is Sept 25. On this date in 1866 geneticist Thomas Hunt Morgan was born. Famous for experiments with the fruit fly by which he established the chromosome theory of heredity.His work played a key role in the field of genetics.Received Nobel Prize for Physiology or Medicine in 1933.

This composite image of the galaxy cluster PLCK G287.0+32.9 shows X-rays from Chandra (blue and purple), radio data from MeerKAT radio telescope (orange and yellow), and optical from PanSTARRS (red, green, and blue). The cluster is located about 5 billion light-years away.

Today is September 24. On this date in 1905 physician and biochemist Severo Ochoa was born. Winner of the 1959 Nobel Prize in Physiology or Medicine for the discovery of "the mechanisms in the biological synthesis of deoxyribonucleic acid (DNA)."

A Hubble image of the star V838 Monocerotis (V838 Mon) reveals dramatic changes in the illumination of surrounding dusty cloud structures. The effect, called a light echo, has been unveiling dust patterns.

Today is Sept 23. On the night of this date,in 1846,astronomer Johann Gottfried Galle working from calculations of Le Verrier discovered the planet Neptune. Astronomer Arago aptly said that Le Verrier had discovered a planet "with the point of his pen".

A beautiful ESO image of the galaxy NGC 4565, which for obvious reasons is also called the Needle Galaxy.

Today is Sept 22. On this date in 1791 physicist and chemist Michael Faraday was born. His numerous experiments contributed greatly to the understanding of electromagnetism. His main discoveries include the principles underlying electromagnetic induction, diamagnetism, and electrolysis.

This ESO image shows the reflection nebula NGC 1788, also referred to as "The Cosmic Bat."

Today is Sept 21. On this date in 1576 physician and mathematician Girolamo Cardano passed away. He gave the 1st clinical description of typhus fever. His book Ars magna (The Great Art) is one of the cornerstones in the history of algebra. See also book "The Equation That Couldn't Be Solved. "

In its September/October issue, Smithsonian Magazine runs an article about the library of the late novelist Cormac McCarthy. I am extremely honored that my book "Is God A Mathematician?" was in his collection! Photo by Wayne Martin Belger.

A fantastic James Webb Space Telescope image of the pair of interacting galaxies known as Arp 107.

Today is Sept 20. On this date in 1996 mathematician Paul Erdős passed away. One of the most prolific mathematicians of the 20th century. Pursued problems in discrete mathematics, graph theory, number theory, and probability theory. My personal Erdős number is 4.

A Hubble image of the planetary nebula NGC 6369, also known as the Little Ghost Nebula. It is at a distance of 2,000-5,000 light-years away.

Today is September 19. On this date in 1843 mathematician and mechanical engineer Gaspard-Gustave Coriolis passed away. He was the first to describe the Coriolis force, an effect of motion on a rotating body, of paramount importance to meteorology, ballistics, and oceanography.

These images of the galaxy NGC 4303 were taken with ESO 's Very Large Telescope (VLT; left) and with the Atacama Large Millimeter/submillimeter Array (ALMA; right).

Today is September 18. On this date in 1752 mathematician Adrien-Marie Legendre was born. Made numerous contributions to mathematics. Well-known and important concepts such as the Legendre polynomials and Legendre transformation are named after him.

This ESO image shows the Flame Nebula and its surroundings captured in radio waves. The Flame Nebula is the large feature on the left. The smaller feature on the right is the reflection nebula NGC 2023.

Today is September 16. #OTD in 1893 biochemist Albert Szent-Györgyi was born. He won the Nobel Prize in Physiology or Medicine in 1937. Credited with first isolating vitamin C and discovering components and reactions of the citric acid cycle and molecular basis of muscle contraction.

Arp 87 in this Hubble image is a stunning pair of interacting galaxies. Stars, gas, and dust flow from the large spiral galaxy, NGC 3808, forming an enveloping arm around its companion. Arp 87 is located approximately 300 million light-years away from Earth.

Today is September 15. On this date in 1929 physicist Murray Gell-Mann was born. Played a preeminent role in development of theory of elementary particles. Introduced the concept of quarks, and the renormalization group. Received the 1969 @NobelPrize in Physics.

An ESO image of the star formation region NGC 3582. The image reveals giant loops of gas ejected by dying stars.

Today is September 14. On this date in 2015 the first direct observation of gravitational waves was made. The waveform matched predictions of General Relativity for a gravitational wave emanating from the merger of 2 black holes of 36  and 29  solar masses.

Today is September 13. On this date in 1916 author Roald Dahl was born. His books have sold more than 300 million copies worldwide. He has been called "one of the greatest storytellers for children of the 20th century".

The Bullet Cluster, made up of two massive galaxy clusters. The vast number of galaxies and foreground stars were captured by Webb in near-infrared light. X-rays captured by Chandra appear in pink. The blue represents the dark matter.

NASA’s Perseverance rover discovered spots on a reddish rock nicknamed “Cheyava Falls” in Mars’ Jezero Crater. Scientists think the spots may indicate that, billions of years ago, chemical reactions in this rock could have supported microbial life; other explanations considered.

Today is September 12. On this date in 1897 chemist and physicist Irène Joliot-Curie was born. She received the 1935 Nobel Prize in Chemistry for the discovery of induced radioactivity.

Today is September 11. New York City skyline with The Tribute in Light 9/11 memorial and the Statue of Liberty. (Image credit: Getty Images).

Today is September 10. On this date in 1839 logician Charles Sanders Peirce was born. The founder of American pragmatism. He wrote on a wide range of topics, ranging from mathematics, logic, physics, geodesy, and astronomy, to psychology, anthropology, history, and economics.

A new Chandra study of the supernova remnant Cas A reveals that just hours before it exploded, the giant star’s interior violently rearranged itself. The Chandra data show the location of different elements: silicon (red), sulfur (yellow), calcium (green) and iron (purple).

Today is September 9. On this date in 1737 physician and physicist Luigi Galvani was born. He studied animal electricity. In 1780, using a frog, he discovered that the muscles of dead frogs' legs twitched when struck by an electrical spark. This was an early study of bioelectricity.

The lenticular galaxy NGC 6684 in this Hubble image is around 44 million light-years away from Earth.

Today is September 8. On this date in 1903 neuroscientist Marthe Vogt was born. Recognized as one of the leading neuroscientists of the twentieth century. She is mainly remembered for her important contributions to the understanding of the role of neurotransmitters in the brain.

An ESO image of the huge stellar nursery nicknamed the Prawn Nebula, which is about 6,000 light-years away from Earth.

Today is September 7. On this date in 1707 naturalist and mathematician Georges-Louis Leclerc, count de Buffon was born. Remembered especially for his comprehensive work on natural history, Histoire naturelle, générale et particulière (begun in 1749).

This Hubble image shows a part of the galaxy NGC 6872 . Its unusual shape is caused by its interactions with the smaller galaxy that can be seen just above NGC 6872, called IC 4970. They both lie roughly 300 million light-years away from Earth.

Today is September 6. On this date in 1908 physicist Louis Essen was born. He performed precise measurement of time and determined the speed of light. In 1955 he developed the 1st practical atomic clock by integrating the caesium atomic standard with quartz crystal oscillators.