Time

Scientists who study time are generally known as chronobiologists. They explore biological rhythms and how they are influenced by time-related factors such as light and temperature.

January 20, 1961 fell on a Friday.

February 6, 1976 fell on a Friday.

June 13, 1949 was a Monday.

Light from an object a trillion miles away (10 to the power of 12) will take around 0.17 years to get to the observer or 62 days.

"Morning."

The abbreviations AM and PM stand for Ante Meridian and Post Meridian, respectively. The terms ante and post mean before and after. The term meridian refers to when the sun is at the middle of its arc across the sky.

Nominally the sun is at its meridian at noon. Since it is *at* its meridian this is neither before nor after the meridian. It *is* the meridian.

Likewise, midnight is neither 12 AM nor 12 PM. It is equally far from both. It is simply 12 midnight.

The military clock is better than the civilian clock for many reasons. One is that eliminates the complexity of specifically accounting for whether a time is before of after midnight. On the military clock noon is read as 1200 hours, and midnight is read as 2400 hours.

The suns lowest point is in the evening 5:00 pm

As of December 28th, 2010, it's been 1 month and 23 days since November 5th.

January 20, 1978 was a Friday.

In the Southern Hemisphere, from June 21 to December 22, the days gradually get longer as this period includes the summer solstice where the sun is at its highest point in the sky. From December 22 to June 21, the days gradually get shorter as this period includes the winter solstice where the sun is at its lowest point in the sky.

A light-year is the distance light travels in one year, approximately 5.88 trillion miles. Therefore, 20 light-years would be around 117.6 trillion miles.

September 12, 1956 fell on a Wednesday.

The real question is: why are the clocks are adjusted in spring and autumn?

Answering this then leads to why it occurs when it does.

The clocks were adjusted because it was noted that by having more hours of daylight in the afternoon and evening, it allowed for more leisure time and less reliance on artificial lighting.

The difference in when the clocks are adjusted comes down to the fact that temperatures change about a month or so after the sun - in the northern hemisphere although the longest day is approx 21 June, the warmest months are July and August when the days are getting shorter. Even into September and the start of October, the evenings are still generally warm (and dry) enough to allow for evening activities.

Similarly, although the shortest day is about 21 December, the coldest period is February to March and so evening leisure activity is not really of importance; once April comes, the days get warmer and evening leisure activity becomes sensible again.

So the adjustment just after the vernal equinox, and a month and a bit after the autumnal equinox (meaning 7 months of advanced time, 5 months of normal time) is where they happen.

According to Einstein's theory of relativity, time is intertwined with space in a four-dimensional spacetime. Time does not have a distinct beginning as it is part of this interconnected continuum. This means that asking when time began may not have a meaningful answer within this framework.

September 30, 1976 was a Thursday.

The standard time for delivery from the UK to Tucson, Arizona, US varies depending on the shipping method chosen. Generally, it can take around 7-14 days for standard international shipping, while express shipping can take around 2-5 days. It's best to check with the specific shipping provider for more accurate estimates.

The Doomsday Clock will not strike midnight. It is simply a very rough and pessimistic estimate. Alterations are made by guesswork.

Should any cataclysm happen it will be far too late for those that alter the clock to do so.

September 20, 1967 fell on a Wednesday.

The current year in the Hindu calendar is 2078. This calendar is also known as the Vikram Samvat calendar and is widely used in India for religious and cultural purposes. It follows a lunar system and is about 56 years ahead of the Gregorian calendar.

When light moves it moves at the amazing speed of 186, 000 mi/sec. However, when light hits a glass block it slows down as glass is a denser substance (light slows down once it enters a denser substance to the one it was traveling through before [air]). The rays that enter the glass first slow down first pulling the other rays closer to normal. Once those rays leave the glass block they pull the rest of the ray away from normal again as they speed up. They speed up as they are now entering air a less dense substance than glass. The angle the light enters at is called the angle of incidence, the angle that the light enters at and leaves at are the same. (See fig. 1A and fig. 1B)

Once a ray of white light enters a triangular prism the light splits into it's spectral components, the colours of the rainbow; Red, Orange, Yellow, Green, Blue, Indigo, Violet. This is dispersion. The source of light could be the sun or in an experiment a ray box. Dispersion happens because of the different wavelengths of white light refract at different amounts depending on the colour, red is refracted the least as it has the longest wavelength so it slows down less and is out of the spectrum first, violet gets refracted the most (The difference between the colours is only milliseconds). As in a prism the colours are refracted at different amounts instead of the rays that enter first dragging the rest the colours refract at different amounts and take different paths allowing us to see them. We know this because if you shine a ray of white light through a triangular prism you can see the spectrum of light leave it

If a ray of light is shone on a flat mirror it is reflected back. The incidence ray is reflected because mirrors are opaque and not transparent so the light can't travel through it. The angle of reflation (the reflected ray) will be the same as the angle of incidence, and because all the light is reflected exactly back you can see your reflection in the mirror. The mirror does not have to be flat though it can be curved. A concave mirror curves inwards magnifying images because it collects parallel light rays and reflects them through a principle focus. A convex mirror a wider range of the image is shown. It reflects the rays so they look like they come from behind.

Reflection is when waves bounce of a surface and travels onward at the same angle but in a different direction; all reflection follows the law of reflection to some point, the law of reflection being that the angle of incidence being the same as the angle of reflection. Refraction on the other hand is the change in the direction of light due to a change in the density of the object it is traveling through causing a change in it's speed. Dispersion, however, is splitting light up into its spectral components. Reflection bouncing light, Refraction changing it's speed and direction, and dispersion splitting it up.

It may be common knowledge that mirrors are used in magic shows (Pepper's ghost) and circuses (hall of mirrors); that glass blocks are used to demonstrate refraction and dispersion helpful to jewellers making diamonds and other precious stones look more impressive- and that they can all be used in theatre. But there are some other uses that are not so common; the prismatic compass makes uses a small capsule that is filled with oil and a magnetized dial. This combination is amplified with an illumination element that helps one of the most accurate compass readings. Prisms are also used in eyeglasses, they are used mainly for double vision, positional correction, or convergence correction.

There are novelty mirrors (MP3 mirror, interactive mirrors, Tetris mirrors and more.) and even an Ironing board mirror made by Aïssa Logerot. Apollo 11 left a mirror on the moon; it is used to reflect laser light from Earth, and with our knowledge of light we can measure the distance from the Earth to the moon by measuring the round-trip time of the light. We now know that the moon is slowly moving away from the Earth. Mirrors can be used to shine a spot of sunlight far away (you reflect the light away from you in the direction you want), and communicate with flashes of light to others if you are out in the wilderness hiking, or even start a fire. And scientists recently discovered a fish that uses its mirrored eyes and lenses to find its way 500-2,500 metres below sea level. It is called the "Brownsnout spookfish".

Glass blocks can be used in decoration to make all sorts of adornments to hang around buildings. They can also be used as fire protection.

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I handed this in as Science H/W so please do not copy and paste the whole thing.

July 10, 1960 fell on a Sunday.

August 6, 1971 fell on a Friday.

June 17, 1962 fell on a Sunday.

The sequence of day and night repeats every 24 hours due to the rotation of the Earth on its axis. This rotation causes different parts of the Earth to be exposed to sunlight at different times, creating the cycle of day and night.

It was a Thursday.