A right triangle is a triangle in which one of the three angles is 90°. The triangle shown below is right-angled because the angle ⦣ACB between sides a and b is 90°. The side opposite the right angle, c, is called the hypotenuse.

One of the most important and best-known…

Credit: NASA/JPL-Caltech/Univ. of Arizona — The Helix Nebula, in the constellation Aquarius, imaged in infrared in 2007 by the Spitzer Space Telescope. It is a planetary nebula about 700 light-years from Earth, with an estimated age of 10,000 years, produced by the matter ejected by a solar-type star in the last stages of its life. The inner ring of the nebula shows a series of cometary-type filaments that Gibson and Schild, authors of the HGD cosmological model, interpret as the effect of the evaporation of the icy atmospheres of a myriad of otherwise invisible planets. Evaporation is caused by the powerful ionizing radiation emitted by the core of a dying star, which will become a white dwarf

At the basis of panspermia is the rejection of abiogenesis. As we have seen, according to Hoyle and Wickramasinghe calculations, the probability that the enzymes essential to the chemistry of living organisms have emerged in their entirety, complete and functional, at the end of a process of purely random accumulation…

Credit: David A. Aguilar / CfA —According to the panspermia hypothesis, around 4 billion years ago, on a young Earth with an atmosphere still devoid of oxygen, frequent impacts of asteroids and comets deposited tons of biological material of extraterrestrial origin in the oceans. As soon as the environmental conditions allowed it, organisms from space managed to survive and reproduce, transforming the Earth into a place teeming with life — a life that still flourishes, despite cataclysms of all kinds and periodic mass extinctions

Bacteria from space

Regarding the incredible replication power of bacteria, in their 1999 book “Astronomical origins of life,” Hoyle and Wickramasinghe wrote (page 101):

Start with a single living cell, say a bacterium. A typical doubling time by binary-fission for a bacterium supplied with appropriate nutrients would be two or three hours. Continuing…

Credit: Shutterstock — Virus H1N1

In the cosmic vision of life typical of panspermia, viruses, particularly retroviruses, have primary importance.

Retroviruses from space

Viruses are biological “machines” extraordinarily effective and, at the same time, incredibly small. They have dimensions in the order of tens or hundreds of nanometers, often less than the wavelength of visible light. The strands…

Credit: ESA — The analyzes carried out on data collected by the Rosetta spacecraft made it possible to establish that the jets emitted by Comet 67P/Churyumov — Gerasimenko contain, among other compounds, organic molecules and molecular oxygen

Comets hosting possible microbial life

As we have seen in the first part of this story, the study’s authors believe it is extremely unlikely that complex biological structures such as enzymes could have formed by chance, especially in an environment subjected to hellish conditions, such as those existing on Earth during the Hadean.

But the…

The protagonists of this story

In 1979, the Italian publishing house Mondadori issued “La Nuvola della Vita” by Fred Hoyle and Chandra Wickramasinghe, a book that I avidly read because it promised answers to the great cosmological questions that, then as now, were at the center of my interests. It was the Italian translation of…

Credit: ALMA (ESO/NAOJ/NRAO)/NASA/ESA/J. Dunlop et al. and S. Beckwith (STScI) and the HUDF Team — This image combines a background picture taken by the NASA/ESA Hubble Space Telescope (blue/green) with a very deep ALMA view of this field (orange, marked with circles). All the objects seen by ALMA appear to be massive star-forming galaxies

As we have already noticed in another post, looking far into space also means looking back in time due to the finite speed of light.

Exploiting this bond between time and distance, astronomers have derived the general lines of the Universe’s evolutionary history by putting together sky observations showing objects…

Credit: NASA, ESA, P. van Dokkum (Yale University), S. Patel (Leiden University), the 3D-HST Team

As many know, light does not propagate instantaneously but has a finite speed, just under 300,000 km per second. One of the strangest and counterintuitive consequences of this limit is that everything we see, even the closest thing, is always an image of the past.

Let us consider the Sun…

In the last fifty years, the ever more widespread diffusion of increasingly cheaper and more powerful home computers has made it possible to fully delegate to machines the execution of calculations that only humans could perform until recently. Among these calculations, we can certainly include finding the square roots of…

Michele Diodati

Science writer with a lifelong passion for astronomy and comparisons between different scales of magnitude.

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