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- Dictionarysemi-darkness/sɛmɪˈdɑːknəs/
noun
- 1. a light level in which it is possible to see, but not clearly: "I made for the door and in the semi-darkness stumbled over one of the wellingtons"
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5 days ago · Three Types of Twilight. In its most general sense, twilight is the period of time before sunrise and after sunset, in which the atmosphere is partially illuminated by the sun, being neither totally dark or completely lit.
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22 hours ago · The hypothesis of dark matter has an elaborate history. [18] [19] In the appendices of the book Baltimore lectures on molecular dynamics and the wave theory of light where the main text was based on a series of lectures given in 1884, [18] Lord Kelvin discussed the potential number of stars around the Sun from the observed velocity dispersion of the stars near the Sun, assuming that the Sun was 20 to 100 million years old.
2 days ago · dark matter, a component of the universe whose presence is discerned from its gravitational attraction rather than its luminosity. Dark matter makes up 30.1 percent of the matter-energy composition of the universe; the rest is dark energy (69.4 percent) and “ordinary” visible matter (0.5 percent).
- Adam Riess
- Dark matter is a component of the universe whose presence is discerned from its gravitational attraction rather than its luminosity.
- Dark matter makes up 30.1 percent of the matter-energy composition of the universe. The rest is dark energy (69.4 percent) and “ordinary” visible m...
- Dark matter’s existence was first inferred by Swiss American astronomer Fritz Zwicky, who in 1933 discovered that the mass of all the stars in the...
- Two varieties of dark matter have been found to exist. The first variety is about 4.5 percent of the universe and made of the familiar baryons (i.e...
1 day ago · Light pollution is the presence of anthropogenic artificial light in otherwise dark conditions. [12][13][14][15] The term is most commonly used in relation to in the outdoor environment and surrounding, but is also used to refer to artificial light indoors.
Oct 3, 2024 · The universal trigger for fear is the threat of harm, real or imagined. This threat can be for our physical, emotional or psychological well-being. While there are certain things that trigger fear in most of us, we can learn to become afraid of nearly anything. Darkness or loss of visibility of surroundings.
5 days ago · Photopsia causes floaters, light flashes, and other abnormalities in the visual field. Floaters are specks and spots that are easier to see during the day. Flashes of light can appear in various forms and are usually more noticeable in the dark.
5 days ago · For example, when it’s dark, the iris muscles expand the pupils to allow more light into the eye. Similarly, it contracts to reduce the amount of light entering the eye when in bright light. The iris muscles enable the eye to shift focus based on near or far objects.
