Current Events in Astronomy

The June solstice is when the sun’s rays are focused most directly on Earth’s Tropic of Cancer, marking the start of summer in North America and South Africa. It’s also when many of us take time to celebrate the end of winter. And it’s an ideal time to get out and enjoy the celestial show, as the sun appears larger in the sky than it does at any other point this year.

The light of a distant galaxy, the Milky Way’s central bar, has finally been measured and dated, revealing that it completed forming just a few billion years ago. Scientists have discovered that a giant planet orbiting another star is about 100 times bigger than Jupiter, making it one of the largest planets ever found outside our solar system. They have also uncovered new clues that suggest life may be possible on Mercury, where a planetwide cache of salt sculpted the chaotic terrain and created potential habitable niches. They have even figured out how to kick-start life in the rocky bodies of Jupiter’s icy moons.

Astronomers have used Hubble to discover “missing” hydrogen, which was produced in the Big Bang but seemed to disappear afterward. By measuring how the light of galaxies in a massive cluster, called Abell 1689, is bent by the gravity of its mass, they were able to identify invisible filaments of hydrogen weaving through space. Hubble also revealed the first direct images of a still-forming, Jupiter-sized exoplanet, and it photographed a comet that appeared to be disintegrating in the Sun’s glare.

Astrophysicists have spotted the first evidence of water vapor on an exoplanet orbiting a red dwarf star, and they have discovered that the atmosphere of the newly discovered planet K2-18b has a temperature at which liquid water could form. They have also used Hubble to capture a rare image of an asteroid with six tails. Hubble also reveals that the Horsehead Nebula, located in the constellation Orion, is the source of the comet 73P/Schwassmann-Wachmann 3, which has been spotted grazing close to Jupiter.

In the 19th century, Irish astronomer William Parsons, 3rd Earl of Rosse built the first of the world’s great telescopes, which enabled astronomers to study the structure of nebulas. The same year, James Bradley discovers that the positions of stars shift back and forth in a cycle known as the aberration of starlight. James Clerk Maxwell shows that the speed at which atoms or molecules move depends on their mass and temperature.

The United States and the Soviet Union send their first space probes to other planets, with Mariner 2 flying by Venus in December 1962 and the more successful Mariner 9 flying by Mars in 1965. NASA also lands the Lunar Prospector on the surface of the Moon, and the NEAR spacecraft reaches an asteroid. Lightning nearly spelled disaster for Apollo 12 seconds after liftoff, but the astronauts’ quick reaction kept them safe and on course to become the first humans on the moon.