Category: astronomy

The original letter in which Galileo argued ag…

The original letter in which Galileo argued against the doctrine of the Roman Catholic Church has been rediscovered in London.

Credit: The Royal Society

Via NatureDiscovery of Galileo’s long-lost letter shows he edited his heretical ideas to fool the Inquisition

There seems there is nothing new or unknown on this find. I recommend taking a look at his essay (in the form of a letter to the Grand Duchess Christina) written in 1615 (around the time the above letter was also written):



Calvin and Hobbes

Sun’s three-dimensional magnetic field during …

Sun’s three-dimensional magnetic field during one full solar rotation (top), and 

composite image generated from

photographs taken on the day of the total eclipse (bottom left) vs. the model’s predictions (bottom right).

Credits: Predictive Science Inc./Miloslav Druckmüller, Peter Aniol, Shadia Habbal/NASA Goddard, Joy Ng


A Perseids meteor catched while photographing …

A Perseids meteor catched while photographing the Andromeda galaxy in 2016.

Via APOD: Meteor before Galaxy

Image Credit: Fritz Helmut Hemmerich

Alluvial fans at Roddy crater on Mars.

Alluvial fans at Roddy crater on Mars.

Via NASA: Fans of Roddy Crater (Image credit: NASA/JPL-Caltech/Univ. of Arizona)

Simulation of the orbits of stars very close t…

Simulation of the orbits of stars very close to the supermassive black hole at the heart of the Milky Way (above). One of these stars, named S2 (below), orbits every 16 years and did pass very close to the black hole in May 2018.

Full story at ESO: First Successful Test of Einstein’s General Relativity Near Supermassive Black Hole

Cosmic microwave background image based o…

Cosmic microwave background

image based on data from the Planck Legacy release, the mission’s final data release, published in July 2018.

The image above is a zoom from next area:

More from the European Space Agency (ESA):

Astronomers Witness the Birth of a Planet

Astronomers Witness the Birth of a Planet

Max Planck Institute for Astronomy

Above: Near infrared image of the PDS70 disk obtained with the SPHERE instrument. The young exoplanet PDS 70 b is clearly detected as a bright signal at the inner rim of the gap (dark region). The emission coming from central star was masked out. The bar to the lower right indicates the linear scale of the image at a distance of 370 light years.

Below: SPHERE image of the newborn planet PDS 70b  (European Southern Observatory)

Credits: Image: ESO/A. Müller, MPIA

The First Asteroid Ever Discovered


On the night of January 1, 1801, Giuseppe Piazzi, a priest in Palermo, Italy, was mapping the stars in the sky. Over three nights, he’d look at and draw the same set of stars, carefully measuring their relative positions.


That night, he measured the stars. The next night, he measured them again. To his surprise, one had moved. The third night, the peculiar star had moved again. This meant it couldn’t be a star at all.


It was something new, the first asteroid ever discovered, which Piazzi eventually named Ceres. Asteroids are bits of rock and metal that orbit the Sun. At over 900 kilometers across, Ceres is a very large asteroid. But through a telescope, like Piazzi’s, Ceres looked like a pinpoint of light similar to a star. In fact, the word asteroid means star-like. You can tell the difference between stars and asteroids by the way they move across the sky. Of course, Piazzi knew none of that at the time, just that he had discovered something new. To learn about Ceres, Piazzi needed to track its motion across the sky and then calculate its orbit around the Sun. 


So each clear night, Piazzi trained his telescope to the heavens. Night after night, he made careful measurements, but from his observations he learned that Ceres was only visible in the sky during the day. It would take another year and a lot of astronomers to nail down Ceres’ path, but we haven’t lost track of it since.


Today, we can do something that Piazzi could only dream of: send spacecraft to study asteroids up close. One spacecraft called Dawn journeyed billions of kilometers over four years to the main asteroid belt. There, it visited Ceres and another asteroid, Vesta. Dawn’s stunning images transformed Piazzi’s dot of light into a spectacular landscape of craters, landslides, and mountains.


From the TED-Ed Lesson The first asteroid ever discovered – Carrie Nugent

Animation by TED-Ed / Reza Riahi

Hubble Space Telescope: Cosmic collision light…

Hubble Space Telescope: Cosmic collision lights up the darkness

Though it resembles a peaceful rose swirling in the darkness of the cosmos, NGC 3256 is actually the site of a violent clash. This distorted galaxy is the relic of a collision between two spiral galaxies, estimated to have occurred 500 million years ago. Today it is still reeling in the aftermath of this event.

Credit: ESA/Hubble, NASA, CC BY 4.0