【推荐2】In 1665, Johannes Vermeer put the last drop of paint onto a canvas and completed his masterpiece “Girl With a Pearl Earring”. But years later on an April day a cyclist named Janine Strong stopped her bike and watched unexpectedly in her fitness app as the snaking line of her cycling route drew the shape of Vermeer’s masterpiece over streets.

Ms. Strong creates what has come to be known as “GPS art”. It is an art category, which means you go outside with your handheld Global Positioning System(GPS) and start moving. The GPS records your movement by creating the dots type of track. This track is a line that details the path you’ve travelled. When you look at this line on the map, then you can see various shapes. Ms. Strong plans her rides in the shapes of stars, birds, lions-and the occasional Vermeer. Then to complete the digital vision of Vermeer’s masterpiece, she biked almost 50 miles around a city to make sure each turn and circle was accurately achieving the covering of Vermeer’s original.

This kind of art form has grown with the widespread availability of satellite tracking for use by ordinary people in fitness apps. It is particularly popular in the app. Strava, and experienced a surge in use during the pandemic. According to a report, more than three billion activities have been uploaded to Strava since the beginning of 2020.

The “GPS art” can be considered the 21st-century version of large-scale drawings on the landscape, a concept gradually known for the world. It even has its own Guinness World Records categories. There was once a couple who completed a 4,500-mile bike ride across Europe that resulted in a 600-mile-wide GPS drawing of a bicycle-the largest such drawing on record.

【推荐3】Everything we know suggests that the universe is unusual. It is flatter, smoother, larger and emptier than a “typical” universe predicted by the known laws of physics. If we reached into a hat filled with pieces of paper, each with the specifications of a possible universe written on it, it is unlikely that we would get a universe anything like ours in one pick—or even a billion.

The challenge that cosmologists face is to make sense of this specialness. One approach to this question is inflation—the hypothesis (假设) that the early universe went through a stage of fast expansion. At first, inflation seemed to do the trick. A simple version of the idea gave correct predictions for the spectrum of fluctuations in the cosmic microwave background.

But a closer look shows that we have just moved the problem further back in time. To make inflation happen at all requires us to fine-tune the initial conditions of the universe. And unless inflation is highly tuned, it leads to a runaway process of universe creation. As a result, some cosmologists (宇宙学家) suggest that there is not one universe, but an infinite number, with a huge variety of properties: the multiverse. There are an infinite number of universes in the collection that are like our universe and an infinite number that are not. But the proportion of infinity to infinity is undefined, and can be made into anything the theorist wants. Thus, the multiverse theory has difficulty making any firm predictions and threatens to take us out of the area of science.

These other universes are unobservable and because chance dictates the random distribution of properties across universes, suggesting the existence of a multiverse does not let us get to anything about our universe beyond what we already know. As attractive as the idea may seem, it is basically a sleight of hand, which turns an explanatory failure into an apparent explanatory success. The success is empty because anything that might be observed about our universe could be explained as something that must, by chance, happen somewhere in the multiverse.

We started out trying to explain why the universe is so special, and we end up being asked to believe that our universe is one of an infinite number of universes with random properties. This makes me suspect that there is a basic but unexamined assumption about the laws of nature that must be overturned.

Cosmology has new questions to answer. Not just what are the laws, but why are these laws the laws? How were they chosen? We can’t just hypothesize what the initial conditions were at the big bang, we need to explain those initial conditions. Thus, we are in the position of a computer program asked to explain its inputs. It is clear that if we are to get anywhere, we need to invent new methods, and perhaps new kinds of laws, to gain a scientific description of the universe as a whole.