Sometimes it seems as if life is passing us by. When we are children, time ambles by, with endless car journeys and summer holidays which seem to last forever. But as adults, time seems to speed up at a frightening rate, with Christmas and birthdays arriving more quickly every year.
There’s no two-ways about it, the Universe is an extremely big place! And thanks to the limitations placed upon us by Special Relativity, traveling to even the closest star systems could take millennia. As we addressed in a previous article, the estimated travel time to the nearest star system (Alpha Centauri) could take anywhere from 19,000 to 81,000 years using conventional methods.
Popular science fiction of the early 20th century depicted Venus as some kind of wonderland of pleasantly warm temperatures, forests, swamps and even dinosaurs. In 1950, the Hayden Planetarium at the American Natural History Museum were soliciting reservations for the first space tourism mission, well before the modern era of Blue Origins, SpaceX and Virgin Galactic. All you had to do was supply your address and tick the box for your preferred destination, which included Venus.
We have accomplished a lot in our (relatively) short time on Earth. We’ve sent humans to the Moon and to live in space, developed massive and sophisticated telescopes to see the farthest reaches of the cosmos, and even rocketed rovers to Mars and probes to the edge of our solar system. However, a number of organizations have taken humanity’s voyage into the final frontier a step farther. NASA, the European Space Agency, and the research collective behind the Search for Extraterrestrial Intelligence (SETI) have been working tirelessly to find out if we are alone, once and for all.
Since the 1960s, astronomers have been aware of the electromagnetic background radiation that pervades the Universe. Known as the Cosmic Microwave Background, this radiation is the oldest light in the Universe and what is left over from the Big Bang. By 2004, astronomers also became aware that a large region within the CMB appeared to be colder than its surroundings.
Boston public schools recently announced that they will shift to using world maps based on the Peters projection, reportedly the first time a US public school district has done so. Why? Because the Peters projection accurately shows different countries’ relative sizes. Although it distorts countries’ shapes, this way of drawing a world map avoids exaggerating the size of developed nations in Europe and North America and reducing the size of less developed countries in Asia, Africa and South America.
Before we really get started on today’s episode, I’d like to share a bunch of really cool pictures created by my friend Kevin Gill. Kevin’s a computer programmer, 3-D animator and works on climate science data for NASA. And in his spare time, he uses his skills to help him imagine what the Universe could look like. For example, he’s mapped out what a future terraformed Mars might look like based on elevation maps, or rendered moons disturbing Saturn’s rings with their gravity.
Chemist John Dalton proposed the theory that all matter and objects are made up of particles called atoms, and this is still accepted by the scientific community, almost two centuries later. Each of these atoms is each made up of an incredibly small nucleus and even smaller electrons, which move around at quite a distance from the centre.
Gravity is a pretty awesome fundamental force. If it wasn’t for the Earth’s comfortable 1 g, which causes objects to fall towards the Earth at a speed of 9.8 m/s², we’d all float off into space. And without it, all us terrestrial species would slowly wither and die as our muscles degenerated, our bones became brittle and weak, and our organs ceased to function properly.
Imagine time running backwards. People would grow younger instead of older and, after a long life of gradual rejuvenation – unlearning everything they know – they would end as a twinkle in their parents' eyes. That’s time as represented in a novel by science fiction writer Philip K Dick but, surprisingly, time’s direction is also an issue that cosmologists are grappling with.