(Left to right): World View Enterprises; USO/iStockphoto; Frans Lanting

Top stories: How cats conquered the world, stratospheric balloons commercialized, and bird eggs explained

A surprisingly simple explanation for the shape of bird eggs

A sandpiper’s egg is shaped like a teardrop, an owl’s like a golf ball, and a hummingbird’s like a jelly bean. A team of scientists made a computer program, dubbed Eggxtractor, to analyze thousands of egg shells from 1400 species. And now they have a convincing explanation for this stunning diversity: The shape of a bird’s egg depends on how much its species flies. See for yourself in our data visualization: Cracking the mystery of egg shape.

Q&A: Why a top mathematician has joined Emmanuel Macron’s revolution

French President Emmanuel Macron has promised his country a revolution. Macron’s brand-new centrist and reformist party, La République En Marche!, won 308 of the 577 seats in the National Assembly Sunday. Science talked to one of En Marche!’s new National Assembly members, mathematician and Fields medalist Cédric Villani, 43, who won 69% of the vote in a constituency south of Paris. Frequent media appearances over the past decade—and his trademark silk ascot and spider brooch—have made him one of France’s best-known scientists.

Commercial balloons in the stratosphere could monitor hurricanes and scan for solar storms

Stratospheric balloons are a low-cost way to get above 99% of the atmosphere. Payloads lifted that high have wide views of Earth and clear views of the stars. For decades, NASA has launched a handful of stratospheric balloons every year. Now, upstart commercial companies like World View are attempting to privatize the stratosphere by launching smaller balloons that can remain in place by surfing stratospheric winds, and scientists are eager to reap the benefits.

Ancient Egyptians may have given cats the personality to conquer the world

For years, historians thought that the ancient Egyptians were the first to domesticate the feline. That is, until 2004, when researchers discovered a 9500-year-old cat buried with a human on the Mediterranean island of Cyprus, revealing that cats had been living with people thousands of years before Egypt even existed. But a new study could put Egypt back in the limelight. A genetic analysis of more than 200 ancient cats suggests that, even if the animals were domesticated outside Egypt, it was the Egyptians who turned them into the lovable fur balls we know today.

Digital reconstruction of ancient chromosomes reveals surprises about mammalian evolution

Humans have 46 chromosomes. Dogs have 78. And a small South American rodent called the red viscacha has a whopping 104. Geneticists have marveled at the chromosomal diversity among mammals for decades, and now, they may know how it happened. A new digital reconstruction of the chromosomes of the ancestor of all placental mammals reveals that these tightly packed structures of DNA and proteins have become scrambled over time—a finding that may help pinpoint possible problem sites in our genomes that underlie cancer and other disease.