The United States Constitution is the highest law of the United States of America. It was signed on September 17, 1787 by the Constitutional Convention in Philadelphia, Pennsylvania. Later, it was put into effect, or ratified, by representatives of the people of the first 13 states. When nine of the states ratified the document, they created a union of sovereign states, and a federal government for that union. That government started on March 4, 1789, which took the place of the Articles of Confederation.
The Constitution of the United States is the oldest federal constitution now in use.
Since 1787, changes have been made to the United States Constitution 27 times by amendments (changes). The first ten of these amendments are together called the Bill of Rights.
When it was signed in 1787, the Constitution had a preamble and seven main parts, called articles.
The Preamble states:
The Preamble is not a law. It gives the reasons for writing the Constitution. The Preamble is one of the best-known parts of the Constitution. The first three words, "We the people," are used very often. The six intentions that are listed are the goals of the Constitution. Why did Southern delegates to the Constitutional Convention not support Congress' power to regulate trade?
They were afraid Congress might try to end Slavery or the Slave trade. (Actually they did not want to pay federally mandated income tax. Lincoln actually wrote in a letter to the south that they could keep slavery where it exists but not expand it if they would end the secession.)
Article One says that the United States Congress (the legislative branch) will make the laws for the United States. Congress has two parts, called "Houses": the United States House of Representatives and the United States Senate. This Article says who can be elected to each part of Congress, and how they are elected.
The House of Representatives has members elected by the people in each State. The number of members from each State depends on how many people live there. Each member of the House of Representatives is elected for two years.
The Senate has two members, called the legislators, from each state, no matter how many people live there. Each Senator is elected for six years. The original Constitution allowed the state legislatures to choose the Senators, but this was changed later by the Seventeenth Amendment.
Article One also says how the Congress will do its business and what kinds of laws it can make. It lists some kinds of laws the Congress and the states cannot make.
Article One also makes rules for Congress to impeach and remove from office the President, Vice President, judges, and other government officers.
Article Two says that the President, Vice President, and executive offices (the executive branch) will carry out the laws made by Congress. This article says how the President and Vice President are elected, and who can be elected to these offices. The President and Vice President are elected for four years by a special Electoral College chosen by the states. The Vice President takes over as President if the President dies, resigns, or is unable to serve.
Article Two also says that the President is the Commander-in-Chief in charge of the United States military. He can make treaties with other countries, but these must be approved by two-thirds of the Senate. He appoints judges, ambassadors, and other officers, but the Senate also must approve these appointments. The President can also veto bills. However, Congress can override the veto and make the bill into a law anyway.
Article Three says there will be a court system (the judicial branch), which includes the Supreme Court. The Article says that Congress can decide which federal courts, besides the Supreme Court, are needed.
Article Three says what kinds of "cases and controversies" these courts can decide. It also requires trial by jury in all criminal cases, and defines the crime of treason.
Article Four is about the states. It says that all states must give "full faith and credit" to the laws of the other states. It also says that state governments must treat citizens of other states as fairly as they treat their own citizens, and must send arrested people back if they have been charged with a crime in another state and fled.
Article Four also says that Congress can make new states. There were only 13 states in 1787. Now there are 50 United States. It says Congress can make rules for Federal property and can govern territories that have not yet been made into states. Article Four says the United States must make sure that each state has a republican form of government, and protect the states from invasion and violence.
Article Five gives two ways to amend, or change, the Constitution.
Any change that is written by Congress or by a convention must be sent to the state legislatures or to state conventions for their approval. Congress decides whether to send a change to the legislatures or to conventions. Three-fourths of the states must approve a change for it to become part of the Constitution.
An amendment can change any part of the Constitution, except one—no amendment can change the rule that each state has an equal number of Senators in the United States Senate.
Article Six says that the Constitution, and the laws and treaties of the United States, are higher than any other laws. It also says that all federal and state officers must swear to "support" the Constitution.
Article Seven says that the new government under the Constitution would not start until conventions in at least nine states approved the Constitution.
Since 1787, Congress has written 33 amendments to change the Constitution, but the states have ratified only 27 of them.
The first ten amendments are called the Bill of Rights. They were argued over during the Constitutional Convention of 1787, but it wasn't until 1791 that they were ratified by two-thirds of the states. These ten additions or changes all limited the power of the federal government. They are:
After the Bill of Rights, there are 17 more changes to the Constitution that were made at different times.
Space-time
Space-time is a mathematical model that joins space and time into a single idea called a continuum. This four-dimensional continuum is known as Minkowski space.
Combining these two ideas helped cosmology to understand how the universe works on the big level (e.g. galaxies) and small level (e.g. atoms).
In non-relativistic classical mechanics, the use of Euclidean space instead of space-time is good, because time is treated as universal with a constant rate of passage which is independent of the state of motion of an observer.
But in a relativistic universe, time cannot be separated from the three dimensions of space. This is because the observed rate at which time passes depends on an object's velocity relative to the observer. Also, the strength of any gravitational field slows the passage of time for an object "as seen by an observer outside the field".
Wherever matter exists, it bends the geometry of spacetime. This results in a curved shape of space-time which can be understood as gravity. The white lines on the picture on the right represent the effect of mass on space-time.
In classical mechanics, the use of spacetime is optional, as time is independent of motion in the three dimensions of Euclidean space. However, when a body is moving at speeds close to the speed of light (relativistic speeds), time cannot be separated from the three dimensions of space. Time, from the point of view of a stationary observer, depends on how close to the speed of light the object is moving.
Many people link space-time with Albert Einstein, who proposed special relativity in 1905. However, it was Einstein's teacher, Hermann Minkowski, who suggested space-time, in a 1908 essay.