Although these results were widely accepted, they were contested. Greek astronomer Eugène M. Antoniadi and English naturalist Alfred Russel Wallace were against the idea; Wallace was extremely outspoken. As bigger and better telescopes were used, fewer long, straight "canali" were observed. During an observation in 1909 by Flammarion with a telescope, irregular patterns were observed, but no "canali" were seen.
Because Mars is the one of the closest planets to Earth in the Solar System, many have wondered if there is any kind of life on Mars. Today we know that the kind of life, if any, would be some simple bacteria-type organism.
NASA maintains a catalog of 34 Mars meteorites, that is, meteorites which originally came from Mars. These assets are highly valuable since they are the only physical samples available of Mars.
Studies at NASA's Johnson Space Centre show that at least three of the meteorites contain possible evidence of past life on Mars, in the form of microscopic structures resembling fossilized bacteria (so-called biomorphs). Although the scientific evidence collected is reliable, and the rocks are correctly described, what made the rocks look like they do is not clear. To date, scientists are still trying to agree if it really is evidence of simple life on Mars.
Over the past few decades, scientists have agreed that when using meteorites from other planets found on Earth (or rocks brought back to Earth), various things are needed to be sure of life. Those things include:
For people to agree on past life in a geologic sample, most or all of these things must be met. This has not happened yet, but investigations are still in progress. Re-examinations of the biomorphs found in the three Martian meteorites are underway.
Liquid water is necessary for life and metabolism, so if water was present on Mars, the chances of life evolving is improved. The Viking orbiters found evidence of possible river valleys in many areas, erosion and, in the southern hemisphere, branched streams. Since then, rovers and orbiters have also looked closely and eventually proved water was on the surface at one time, and is still found as ice in the polar ice caps and underground.
So far, scientists have not found life on Mars, either living or extinct. Several space probes have gone to Mars to study it. Some have orbited (gone around) the planet, and some have landed on it. There are pictures of the surface of Mars that were sent back to Earth by the probes. Some people are interested in sending astronauts to visit Mars. They could do a better search, but getting astronauts there would be difficult and expensive. The astronauts would be in space for many years, and it could be very dangerous because of radiation from the sun. So far we have only sent unmanned probes.
The most recent probe to the planet is the Mars Science Laboratory. It landed on Aeolis Palus in Gale Crater on Mars on 6 August 2012. It brought with it a mobile explorer called 'Curiosity'. It is the most advanced space probe ever. Curiosity has dug up Martian soil and studied it in its laboratory. It has found sulfur, chlorine, and water molecules.
Some famous stories were written about this idea. The writers used the name "Martians" for intelligent beings from Mars. In 1898, H. G. Wells wrote "The War of the Worlds", a famous novel about Martians attacking the Earth. In 1938, Orson Welles broadcast a radio version of this story in the United States, and many people thought it was really happening and were very afraid. Beginning in 1912, Edgar Rice Burroughs wrote several novels about adventures on Mars.
Notes
Mac OS
"For the Apple computer family, see macOS"
The Macintosh Operating System (Mac OS) is a program that allows a Macintosh computer to operate and be used. Mac OS was first made by Apple Inc. in 1984. In those days Mac OS was called Macintosh System Software – which was shortened to System or SSW (System Software). The term "Mac OS" first appeared in the splash screen for System 7.5.1, but was not adopted as the new name until the release of Mac OS 7.6.
The latest version of Mac OS is Mac OS 11 Big Sur.
Apple Macintosh
The Apple Macintosh or just “Mac” is a line of personal computers made by the American company Apple Inc. The Macintosh was one of the first computers in which the people could use a mouse for pointing on a screen which had icons. This new way of working with a computer (interface) was known as graphical user interface. It was this feature of the Macintosh that made it so popular.
The Apple–Intel transition was when Apple changed the CPU of Macintosh computers from PowerPC processors to Intel x86 processors. It was announced at the 2005 World Wide Developers Conference. Steve Jobs announced it.
Macintoshes were different than other personal computers for many years based on their central processor unit (CPU). At the start, Macs used Motorola 68000 chips instead of Intel chips. Later, Macs used PowerPC chips. In 2006, Macs started to use Intel chips. Today, Macs are sold with Intel quad-core i7 chips.
The Mac does not have the Windows operating system installed on it. It has its own range of operating systems, known as macOS. The newest operating system is known as “Catalina". Macs can run both Windows and macOS at the same time with help of a program called “Boot Camp”, which comes on every Mac.
In general, Macintosh computers cost more than other computers of the same speed.
Metre
A metre (US spelling, "meter") is the basic unit of length in the SI measurement system. The symbol for the metre is m. The first meaning (in the French Revolution) was one ten-millionth of the distance between the Earth's equator and the North Pole along the Paris meridian. The metre is now defined as the distance light travels in a vacuum in 1/299,792,458 of a second.
In the imperial system of measurement, one yard is 0.9144 metres (after international agreement in 1959), so a metre is very close to 39.37 inches: about 3.281 feet, or 1.0936 yards.
"*Note: units in bold are the most commonly used."
https://www.youtube.com/channel/UCLjFezysfbVZFZ_jeLB0iHg
Magnifying glass
A magnifying glass is a lens through which can be used to make things appear bigger, so you can see them better. It is used in many applications and manual operations, e.g., for examining postage stamps in philately.
The magnifying glass consists of a piece of convex-shaped glass or plastic. It has to be held at the right distance between the eye and the object for the object to be in focus. The magnifying glass usually comes with a handle. A telescope is a more advanced kind of magnifying glass and consists of at least two glass lenses.
A pair of binoculars is like a telescope for each eye. "Spectacles" or eyeglasses also use lenses to correct a person's vision.
Molecule
A molecule is the smallest amount of a chemical substance that can exist. If a molecule were split into smaller pieces, it would be a different substance.
Molecules are made up of atoms that are stuck together in a particular shape or form. Not all combinations of atoms are equally possible; atoms make certain shapes in preference to others. Also, they have different valency. For example, oxygen atoms always have two bonds with other atoms, carbon atoms always have four bonds with other atoms, and nitrogen atoms always have three bonds with other atoms.
In the kinetic theory of gases, the term "molecule" is often used for any gaseous particle regardless of its composition. According to this definition, noble gas atoms are considered molecules as they are in fact monoatomic molecules.
In gases like air, the molecules are just flying around. In liquids like water, the molecules are stuck together but they can still move. In solids like sugar, the molecules can only vibrate. In the fourth state of matter known as plasma, the atoms are ionized and cannot form molecules.