Music: Star of the Conqueror by Dhruva Aliman - https://dhruvaaliman.bandcamp.com/album/the-wolf-and-the-river Zoom from subatomic particles to the most distant galaxies. Travel from the quantum foam of space-time to the edge of the universe and learn about everything in between. Carl Sagan told us that there are more stars in the universe than there are grains of sand on all of the Earth's beaches. At the same time, there are more H2O molecules in just 10 drops of water than there are stars. Get a sense of the true scale of our universe ranging from the unimaginably small to the unimaginably big, the scale of the universe is mind-boggling. Watch to try to wrap your head around it.
Atoms are among the smallest objects that are found in the Universe.
Our bodies, in common with all material on the Earth, the planets of our Solar System, the Sun, stars and galaxies are composed of what we call matter. Much of the matter in and among the stars is composed of atoms and molecules that are familiar here on Earth. An atom is made up of particles called electrons which occupy a cloud-like structure around a central nucleus composed of protons and neutrons. The electrical attraction between negatively charged electrons and positively charged protons holds the atom together. A chemical element is defined by the number of protons in the nucleus. Hydrogen has one proton, helium has two and so on. A molecule is a group of two or more atoms (see Figure 2).
Many of the molecules in the human body are extremely complex combinations of atoms of different elements, but the simplest atom, hydrogen is the most common chemical element in the Universe, and helium is the second most common.
Figure 2 The structure of a water molecule which consists of two atoms of hydrogen and one of oxygen. The structure of the oxygen atom is also shown.
Atoms are among the smallest objects that are found in the Universe (individual hydrogen atoms are abundant in the interstellar medium - the space between the stars). Everyday units for length (such as metres) are just as inappropriate for these tiny objects as they are for defining the vast distances between stars.
When measuring the scale of the Universe it's necessary to consider the smallest and largest objects and distances and how they're defined. The physical quantity of interest is length (it may be the diameter of an object or its distance from us).
The scale of the Universe from atoms to galaxies. The size of an atom is about one-ten-billionth of a metre, and the nucleus of that atom is around a hundred thousand times smaller still! Clearly some different units for distance are needed that are more appropriate for the very small and very large. One way to do this is to use units that are appropriate for a given scale. For example, the size of an atom is better described by a unit that is one-ten-billionth of a metre in size called an ångström (Å), whereas distances to stars can be measured in light-years (ly).
Atoms are among the smallest objects that are found in the Universe.
Our bodies, in common with all material on the Earth, the planets of our Solar System, the Sun, stars and galaxies are composed of what we call matter. Much of the matter in and among the stars is composed of atoms and molecules that are familiar here on Earth. An atom is made up of particles called electrons which occupy a cloud-like structure around a central nucleus composed of protons and neutrons. The electrical attraction between negatively charged electrons and positively charged protons holds the atom together. A chemical element is defined by the number of protons in the nucleus. Hydrogen has one proton, helium has two and so on. A molecule is a group of two or more atoms (see Figure 2).
Many of the molecules in the human body are extremely complex combinations of atoms of different elements, but the simplest atom, hydrogen is the most common chemical element in the Universe, and helium is the second most common.
Figure 2 The structure of a water molecule which consists of two atoms of hydrogen and one of oxygen. The structure of the oxygen atom is also shown.
Atoms are among the smallest objects that are found in the Universe (individual hydrogen atoms are abundant in the interstellar medium - the space between the stars). Everyday units for length (such as metres) are just as inappropriate for these tiny objects as they are for defining the vast distances between stars.
When measuring the scale of the Universe it's necessary to consider the smallest and largest objects and distances and how they're defined. The physical quantity of interest is length (it may be the diameter of an object or its distance from us).
The scale of the Universe from atoms to galaxies. The size of an atom is about one-ten-billionth of a metre, and the nucleus of that atom is around a hundred thousand times smaller still! Clearly some different units for distance are needed that are more appropriate for the very small and very large. One way to do this is to use units that are appropriate for a given scale. For example, the size of an atom is better described by a unit that is one-ten-billionth of a metre in size called an ångström (Å), whereas distances to stars can be measured in light-years (ly).
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