BRAINDUMP
Is the amount of energy in the universe constant?
Amazing answers to your curious questions
The first law of thermodynamics – the science of heat and energy that governs the behaviour of the universe – states that energy cannot be created or destroyed, only transferred from one form to another. So despite appearances, the amount of energy in the cosmos is constant. However, the cosmos is filled with strange forms of energy that we know very little about – just four per cent of the universe is locked up in the mass of visible matter, about 25 per cent is unknown dark matter and about 70 per cent is mysterious dark energy, which seems to be a kind of ‘negative gravity’ driving the expansion of the cosmos. Some physicists even think that normal and ‘negative’ forms of energy balance out so that the universe’s overall energy is not only constant, it’s zero.
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WHEN WAS THE RIALTO BRIDGE IN VENICE BUILT?
The Rialto Bridge is one of only four bridges that span the Grand Canal in Venice, Italy. The stone bridge was commissioned in the late-16th century to replace the previous wooden structure, which was prone to collapse. Blueprints were submitted by the most eminent architects of Renaissance Italy, including Michelangelo, but the commission went to the relatively unknown Swiss-born Antonio da Ponte in 1588, whose design, featuring a single broad arch, was completed in 1591. Today, the Rialto Bridge is one of the most visited tourist sites in the city, featuring an arcade of shops and excellent views of the famous gondolas passing beneath.
WHAT CAUSES DIZZINESS?
Dizziness – sometimes referred to as lightheadedness – can be brought on by a wide range of factors. In general, people who feel dizzy describe it as a feeling of being offbalance. However, other experiences such as spinning room-type sensations are also common. The most frequent causes of dizziness include viral illnesses that affect the ear – often resulting in vertigo, migraines, hyperventilation, and thus a lack of oxygen brought on through stress, as well as low blood sugar levels. Despite many people feeling dizzy at odd moments throughout their day-to-day lives, the good news is that in most cases it’s not an indication of a serious underlying issue.