Manmade radio waves have been used since the 19th century for communication. Radar was developed in the 20th century, using radio waves to 'see' distant objects by bouncing waves off an object and seeing how long it takes for the waves to return. Radios also use these waves to send and receive information.
Radio waves from other planets were first discovered in the 1930s by Karl Guthe Jansky, working for Bell Laboratories. Bell was detecting noise (electronics) on radio channels, and had Jansky try to find the source of this static, or interference. After identifying noise that came from lightning, he spent much time looking into the remainder. Surprisingly, some of the interference was coming from space! This discovery eventually led astronomers to look at radio waves along with light waves to find things in the sky. These radio astronomers use giant Radio telescopes, shaped like satellite dishes, to gather and study the waves.
Radio waves are used for many things today. Broadcasting and communications satellites and mobile phones and many computers communicate by radio waves.
Bridge
A bridge is a structure to cross an open space or gap. Bridges are mostly made for crossing rivers, valleys, or roads. Nowadays most big bridges are made to carry vehicles but people have also walked across bridges for thousands of years. Bridges called highway overpasses carry a road over another road.
Military bridges are portable, so that they may be easily moved to where they are needed. This makes them much more complex than most civilian bridges.
The first man-made bridges were probably made from cut wood or stones. Some stone bridges have lasted thousands of years. In recent centuries large bridges are made mostly of steel. They do not last as long. Many bridges are in a state of disrepair.
There are five major structural types of bridges:
Mysticism
Mysticism is the belief that people can "directly" experience God or true reality, rather than through books, ritual or other people. People who practice this are called "mystics".
Mystics exist within most religions, though not all people who practice religions are mystics. Mystics may experience visions or dreams, or hear God as a voice.
Some examples of Hindu mystics:
Some examples of Christian mystics:
Islamic Mysticism is known as "Tassawuf" (or Sufism) and a detailed list of Muslim Sufi mystics is given on the Sufism page.
Some examples of Jewish mystics:
Some examples of Buddhist mystics:
Ontario
Ontario is a province of Canada. It is in the eastern half of Canada, between Manitoba and Quebec. Ontario has the most people of any province, with 13,150,000 in 2009, and is home to the biggest city in Canada, Toronto, which is also the capital of the province. In the eastern part of the province, placed on the border with Quebec, is Ottawa, the capital of Canada, located on the Ottawa River.
Ontario also has the second largest land area, with 1,076,395 km²; only Quebec is larger by size. (Nunavut and Northwest Territories are also larger, but are called "territories" and not "provinces"). The province has one of the longest borders with the United States and there are several border crossings including the one at Niagara Falls. Along this border are 4 large lakes called Lake Ontario, Lake Erie, Lake Huron, and Lake Superior. They each are partly in Ontario and partly in the United States, and the border runs through them, but not Lake Michigan, which is entirely in the United States. These five lakes are together are called the Great Lakes.
There are a number of symbols that represent the province of Ontario. The flag is red with the British Union Jack in the top left corner and the provincial shield is on the right hand side of the flag. The provincial bird is the loon, and the provincial flower is the trillium. It has three flower petals and it is usually white but some times is pink or purple.
Ontario became part of Canada when it was created in 1867. Before 1840, it was known as Upper Canada, which was a colony in the British Empire. Between 1840 and 1867 it was known as Canada West. The government of Ontario sits at Queen's Park in Toronto. The leader of the government is called the "Premier", and the current Premier is Doug Ford. There is also a Lieutenant Governor who represents the Queen, and the current Lieutenant Governor is Elizabeth Dowdeswell.
Ontario is very large, so sometimes people break it into two. The two parts are called Northern Ontario and Southern Ontario. Most of the people in Ontario live in the south, and that is where the big cities are. The big cities in Southern Ontario are Toronto and the rest of the Greater Toronto Area, Ottawa and the National Capital Region, Hamilton, London, Windsor, and Sarnia. The cities in the north are smaller. In the far north of Ontario hardly any people live at all, and there are no roads or railways making it difficult to even get to those places.
Much of Ontario gets lots of snow in the winter. In the summer, it can get very hot in the south parts. In some big cities, there is smog in the summer.
Manitoba
Manitoba is a province of Canada. It lies roughly in the centre of Canada.
Manitoba is the 6th largest province with area. It has the fifth largest number of people, with 1,379,584 in 2020. People from Manitoba are called "Manitobans".
People have been living in Manitoba for thousands of years. Both the Hudson's Bay Company from England and many people from France moved to Manitoba during the 17th, 18th, and 19th centuries. It became part of the Northwest Territories in 1869. The Red River Rebellion, which was started by Louis Riel, began in Manitoba.
Manitoba became part of Canada on 12 May 1870. It included only the southern part which is nearest to the United States. But parts of the Northwest Territories were added to Manitoba later on.
The capital of Manitoba is the city of Winnipeg. Other large cities in Manitoba include Steinbach and Brandon.
The people of Manitoba elected a legislature. The leader of the government, who is called the "Premier", is the leader of the largest party in the legislature. There is also a Lieutenant Governor, who represents the Queen. Right now, the premier of Manitoba is Greg Selinger and the Lieutenant Governor is Philip S. Lee.
The main political parties in Manitoba are the New Democratic Party, the Progressive Conservative Party of Manitoba, and the Liberal Party.
Head of government
The head of government is the leader of the executive branch of a nation's government. This is not always the same person as the head of state. Official titles for heads of government include Premier or Prime Minister.
For example, in the United States, the president is both the head of state and the head of government. In the Republic of Ireland the president is the head of state but the Taoiseach is the head of government. In most modern monarchies the king (or queen) is the head of state but not the head of government, as is the case of Japan and the UK, for example.
The head of state of some countries has no power over law and justice, for example, the Bundespresident of Germany.
Saskatchewan
Saskatchewan (; "") is a province in Canada. About 1 million people live in Saskatchewan. Most of its population lives in the southern part of the province. The primary industry in Saskatchewan is agriculture (farming).
Saskatchewan is known for its wide horizons. The land is very flat in the south, so you can sometimes see far away. Not all the land is flat prairie. There are beautiful scenic woodlands and forests in the central and northern regions and parklands with lakes for fishing. The province is marked by and named after the North and South Saskatchewan rivers that run through it. The province is nicknamed "The Land of Living Skies".