Our solar system officially has eight planets and one star: the Sun. The discovery of an object larger than Pluto in 2005 rekindled the debate over whether such objects, belonging to the Kuiper Belt – a collection of icy bodies located beyond Neptune – should be called planets. Pluto and other large members of the Kuiper Belt are now considered “dwarf planets.”
A woodpecker drives its head into a piece of wood at deceleration forces of up to 1,200 times the force of gravity with each blow (and it’s estimated they do this about 12,000 times in a day). And yet, they don’t get brain damage. For materials scientists like Joanna McKittrick @ucsd, who work on bio-inspired materials, this is intriguing stuff …
The skull is a very nice, impact-resistant shell, so we are looking at their skulls - and their tongues also play a role into this, too. Amazingly enough, their tongues can wrap around their skulls …. if you like nature and you are curious about animals, almost everything you see, you’d say, why that, what is that function and can we duplicate that in the lab?
Originally, the word “nebula” referred to almost any extended astronomical object (other than planets and comets). The etymological root of “nebula” means “cloud”. As is usual in astronomy, the old terminology survives in modern usage in sometimes confusing ways. We sometimes use the word “nebula” to refer to galaxies, various types of star clusters and various kinds of interstellar dust/gas clouds. More strictly speaking, the word “nebula” should be reserved for gas and dust clouds and not for groups of stars.
By order in which they appear from top to bottom, left to right, here are the main types and some provided examples for visual reference:
Planetary Nebulae: Sh2-188
Planetary nebulae are shells of gas thrown out by some stars near the end of their lives. Our Sun will probably evolve a planetary nebula in about 5 billion years. They have nothing at all to do with planets; the terminology was invented because they often look a little like planets in small telescopes. A typical planetary nebula is less than one light-year across.