Space and astronomy news
Time is an illusion caused by the passage of history (Douglas Adams 1952-2001). The way that we deal with time is central to a major current schism in physics. Under classic Newtonian physics and also quantum mechanics – time is absolute, a universal metronome allowing you determine whether events occur simultaneously or in sequence. Under Einstein’s …
Continue reading “Astronomy Without A Telescope – Is Time Real?”
[/caption] A wormhole is a hypothetical “tunnel” connecting two different points in spacetime, and in theory, at each end of the wormhole there could be two universes. Theoretical physicist Nikodem Poplawski from Indiana University has taken things a step further by proposing that perhaps our universe could be located within the interior of a wormhole …
Continue reading “Is Our Universe Inside Another Larger Universe?”
The gravity formula that most people remember, or think of, is the equation which captures Newton’s law of universal gravitation, which says that the gravitational force between two objects is proportional to the mass of each, and inversely proportional to the distance between them. It is usually written like this (G is the gravitational constant): …
[/caption] The cosmological constant, symbol Λ (Greek capital lambda), was ‘invented’ by Einstein, not long after he published his theory of general relativity (GR). It appears on the left-hand side of the Einstein field equations. Einstein added this term because he – along with all other astronomers and physicists of the time – thought the …
[/caption] The constant of gravity, or gravity constant, has two meanings: the constant in Newton’s universal law of gravitation (so is commonly called the gravitational constant, it also occurs in Einstein’s general theory of relativity); and the acceleration due to gravity at the Earth’s surface. The symbol for the first is G (big G), and …
[/caption] Some of the most frequently asked questions we get here at Universe Today and Astronomy Cast deal with black holes. Everyone wants to know what conditions would be like at the event horizon, or even inside a black hole. Answering those questions is difficult because so much about black holes is unknown. Black holes …
Continue reading “Could a Black Hole Fit in Your Computer or In Your Pocket?”
[/caption] Several different spacecraft have exhibited unexplained changes in speed during gravity assists when flying by Earth. First there was Galileo in 1990 and 1992, NEAR, which flew by Earth in January 1998, and then Cassini in August of 1999. Rosetta — the ESA spacecraft that recently flew by an asteroid – swung by the …
[/caption] We’ve all wondered at some point or another what mysteries our Solar System holds. After all, the eight planets (plus Pluto and all those other dwarf planets) orbit within a very small volume of the heliosphere (the volume of space dominated by the influence of the Sun), what’s going on in the rest of …
Both Pioneer probes are approximately 240,000 miles (386,000 km) closer to the Sun than predicted by calculation. Scientists have been arguing over the cause of this mysterious force for a decade and reasons for the Pioneer anomaly range from the bizarre to the sublime. Is it a simple fuel leak, pushing the probes of course? …
Continue reading “The Pioneer Anomaly: A Deviation from Einstein Gravity?”
So what did exist before the Big Bang? This question would normally belong in the realms of deep philosophical thinking; the laws of physics have no right to probe beyond the Big Bang barrier. There can be no understanding of what was there before. We have no experience, no observational capability and no way of …
Continue reading “What was Before the Big Bang? An Identical, Reversed Universe”