A mere two years after completing his daring General Theory of Relativity in 1915 — where gravity is interpreted as resulting from the curvature of space and time around a massive body — Albert Einstein wrote a daring article, taking on the whole universe under his new lens.

Given that mass tells space how to bend, he reasoned, if he knew the mass contained in the entire universe, he could derive its geometry as a whole. For the first time in history, a single mind attempted to derive the shape of the cosmos not from theological or philosophical arguments, as so many had before, but as the result of solid physical and mathematical reasoning.

As an intellectual move, it took a lot of courage. In what follows, I’ll attempt to take you through Einstein’s reasoning, as close as possible to the famous 1917 paper.

How would someone apply equations that worked very well for solar-system-scale problems to a much grander scale?

Modern Cosmology Turns 100

Image: ESO/INAF-VST/OmegaCAM

A mysterious unknown object, that many researchers claim is an ‘alien probe’, is set to fly past Earth in 2017. The strange object which is now known as (1991VG) was first spotted way back in November 1991 by astronomer James Scotti at the University of Arizona.

The object, only about 10 meters in diameter, exhibited strange properties that raised the astronomer’s suspicion. It moved faster than expected for a space object its size, and had an unusually fast rate of rotation. It also exhibited an anomalous pattern of brightness variation that suggested it was not an ordinary main-belt asteroid.

We looked into all the possibilities for it being man-made, ” Scotti told Motherboard. ‘There were a few possible spacecraft and rocket bodies that might be 1991 VG.’ ‘But when we looked into it further, we were able to eliminate each of them.’ This strange object shows an unusual rapid rate of rotation and its brightness appears to fluctuate. This behaviour, has never been seen before from any asteroid of its size.

Comet PanSTARRS in the Southern Fish : Now approaching our fair planet this Comet PanSTARRS , will be affected by the light of a nearly Full Moon, though. Still the comets pretty green coma is about the apparent size of the Full Moon in this telescopic portrait, captured on June 12 from the southern hemispheres Siding Spring Observatory. The deep image also follows a broad, whitish dust tail up and toward the left in the frame, sweeping away from the Sun and trailing behind the comets orbit. Buffeted by the solar wind, a fainter, narrow ion tail extends horizontally toward the right. On the left edge, the brightest star is bluish Iota Piscis Austrini. Shining at about fourth magnitude, that star is visible to the unaided eye in the constellation of the Southern Fish. via NASA

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