The Oort Cloud, theorized by Jan Oort in 1950, is a vast, icy structure beyond the Solar System, containing trillions of objects. It is divided into the sparse outer cloud and the denser, doughnut-shaped inner cloud. Evidence for its existence includes the orbits of long-period comets. Galactic tides and interactions with giant planets likely contributed to its formation and distribution of icy bodies.
Tag: Space
eBooks from Explaining Science 2024
Update 30 August 2025 I have extensively expanded and rewritten all three “A Short Guide to…” e-books. I will make these books available on Kindle for a competitive price. However, in future I won’t do any deals where I offer free or discounted prices on these books for a limited time period. I believe the… Continue reading eBooks from Explaining Science 2024
Gliese 710: The Closest Future Star Encounter
Updated 21 November 2025 In 1.3 million years’ time the star Gliese 710 is forecast to pass within 0.166 light years of the Solar System, 25 times closer than Proxima Centauri which is our current nearest star (excluding the Sun of course). The close approach of Gliese 710 will be the strongest disrupting encounter known… Continue reading Gliese 710: The Closest Future Star Encounter
September 22 2024 – the equinox
In 2024 September 22 is the date of the September equinox and is also the first day of autumn (or the first day of spring if you're one of my readers in the Southern Hemisphere). In this post I’ll talk about the equinoxes and discus the commonly held, but not quite correct, view that they… Continue reading September 22 2024 – the equinox
Commercial Space Travel
Although a small number of extremely wealthy space tourists have paid millions of dollars for orbital spaceflight, by their very nature only a handful of people can take part in these spaceflights each year. It looks like Virgin Galactic will start commercial spaceflights aimed a larger audience soon. According to the Virgin Galactic Website Galactic… Continue reading Commercial Space Travel
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