The Earth is like our mother.She gives live to all the living things on the Earth.And she provice us with air、food、water and other things we need for living.Once she was beautiful ahd rich.But mow she is crying, becacuse she is becoming dirtier and dirtier, poorer and poorer. It'...
In 1936, Edwin Hubble classified galaxy shapes in the Hubble Sequence. Elliptical Galaxy These have a faint, rounded shape, but they're devoid of gas and dust, with no visible bright stars or spiral patterns. They also don't have galactic disks, which we'll learn about below. Their ...
"Both have testes and ovaries, but how the eggs and sperm move around is different," he said. "Birds' reproductive tracts, their urinary tracts, and guts all empty into a single chamber that opens to the outside, the cloaca. Female birds have no uterus or vagina, the oviduct empties i...
AA desert refers to a barren section of land, mainly in arid and semi-arid areas, where there is almost no precipitation, and the environment is hostile for any creature to inhabit. Deserts have been classified in a number of ways, generally combining total precipitation, how many days the ...
If you believe the whole staring-at-the-sun-makes-you-go-blind thing (which is actually true), you’re probably not doing a whole lot of sun-gazing. But it’s a real marvel: The sun warms our planet every day, provides the light by which we see and is necessary for life on Eart...
The above title reminds us of Robert Wise's 1951 science fiction film (and the remake released in 2008 as well), but this time the planet is not threatened by aliens, but by a Terran nanosized enemy with comparable power. Since the World Health Organization (WHO) declared the new Corona...
Recently, my university is conducting a survey to collect our opinions of online classes. I'm going to summarize the students' responses about the advantages and disadvantages of online courses, and give suggestions for improvement. Online courses have many obvious advantages. First of all, online...
"While not classified as 'light reading,' How Zoologists Organize Things by British author David Bainbridge is a fascinating look at humanity's struggle to understand the animals with which we share theworld."–WhiteTail Magazine"This book is so much more than an explanation of the title; it...
Astrobiologists seek to understand (among other things) how life arose and evolved on Earth, what governs the way life is organized and what makes a planet habitable. Astrobiology combines the disciplines of biology, chemistry, physics, geology and astronomy. Often, astrobiologists must use the ...
More than 25 years later, Pope is one of the world's leading UFO experts and a fixture at UFO conferences like Contact in the Desert and the International UFO Congress, where he lectures on government-sponsored UFO investigations, conspiracy theories and the disclosure of classified government doc...