From neutron stars colliding to our solar system’s first visitor, 2017 was an amazing year for space discoveries. While the year had some sad moments, like the end of the 20–year long Cassini mission, we also learnt a huge amount about this vast Universe in which we live. Here’s the best of space in 2017.

An incredible year for gravitational waves

The Nobel Prize for Physics was awarded to the Ligo team that has now spotted three instances of gravitational waves coming from black holes merging. The first of these was announced in February 2016 and the second in June this year.

Then, in October, another merger was detected – but this time from two neutron stars. Not only this, but the team also found electromagnetic radiation coming from the event and gamma-ray bursts given off just seconds later.

Neutron stars are among the strangest stars in the Universe. Produced when the largest stars come of the end of their life, run out of fuel and collapse in on themselves, neutron stars are the smallest and most dense stars can get. Just one teaspoon of neutron star material is as heavy as the Great Pyramid of Giza. When two collide, a lot of crazy science goes on.

Arguably the biggest space discovery of the year, the discovery of the merger in gravitational waves and electromagnetic radiation has marked the start of a ‘new era’ in astrophysics.

A super-Earth found 40 light years away

M. Weiss/CfA

An exoplanet discovered 40 light years away caused excitement among astronomers in April, as it has the potential to give us the best opportunity ever to find alien life. The ‘super-Earth’ called LHS 1140b is around 1.4 times the size of our planet but seven times its mass. It is rocky, temperate and orbits a quiet star in our galactic neighbourhood.

“I am really, really excited about this discovery,” David Charbonneau, study author and professor of astronomy at Harvard University said at the time. “This is the one we’ve been hunting for all these years!”

Ten new possibly habitable planets found

NASA/JPL-Caltech

In June, Nasa revealed ten new potentially habitable worlds. They were part of a group of 219 exoplanets revealed by the space agency in its eighth Kepler planet catalogue.

All the planets are Earth-sized and in the habitable zone of their stars. This means they are at just the right distance for liquid water to exist on their surfaces. Nasa’s Kepler space telescope has now discovered 4,034 candidate exoplanets. Out of these, 2,335 have been confirmed as planets, and are located in the Cygnus constellation.

Jupiter’s spot up close

NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt

In July, images from Nasa’s Juno spacecraft revealed the gas giant in a completely new level of detail, showing its Red Spot to be “a tangle of dark, veinous clouds weaving their way through a massive crimson oval.”

Since it arrived at the planet in July 2016 Juno has taken thousands of photographs and used eight on-board sensors to capture detailed readings about how it formed and its chemical composition. Its mission ends is February 2018 with a drive into Jupiter’s atmosphere.

Water on the moon

Olga Prilipko Huber

The Moon holds more water than we thought in its interior, according to research published in July, meaning humans could one day make the most of it as a space resource.

The study looked at a substance found on the Moon called pyroclastic deposits, which are made mostly of volcanic glass beads formed during ancient explosive eruptions. In the past, these have been thought of as potentially useful sources for elements like iron and titanium.

The authors behind the research say we have reason to believe they also contain water, which could be extracted by astronauts on the moon one day.

The end of an era for Cassini

Nasa

After almost 20 years since Nasa’s Cassini mission launched, the spacecraft went on a collision course towards Saturn this September. In its lifetime the spacecraft traveled more than one billion miles and helped reveal the secrets of Saturn and its moons.

As it descended to a fiery end, Cassini gathered data that will create maps of Saturn’s gravity and magnetic fields. This will shed light on the planet’s composition and help scientists understand just how quickly Saturn is rotating. Although Cassini is gone, scientists will keep working on its data for years to come.

Runaway stars

Amanda Smith

At the very edge of our galaxy, some stars are moving fast enough that they have the energy needed to escape its gravitational clutches. Now, it turns out, ours might not be the first galaxy these stars have escaped from.

Previously, physicists thought these incredibly fast stars were accelerated to such great speeds by the supermassive black hole at the centre of our galaxy. But a study published in July showed these ‘runaway’ stars at the edge of the Milky Way were thrown our way from another nearby galaxy.

We’re closer than ever to Planet Nine

Tom Ruen/ESO

In January 2016, a pair of astronomers published a paper that changed the direction of modern astronomy. The paper predicted the existence of another, huge planet lurking far beyond Neptune, in the most distant realms of our solar system.

In September this year, one of the authors of the original paper decided it was time it got an update. In a new paper, Konstantin Batygin, a Caltech professor of planetary science, narrowed down the hunt for the planet. “With our new understanding of how Planet Nine sculpts the observed patterns in the data, we have been able to zoom in on its true orbit further,” Batygin says.

Our first interstellar visitor

In November, the first planetary body to come to our solar system form somewhere else was discovered. The object, originally named A/2017 U1, was spotted on October 18 when it was already heading away from Earth. It had been closer to the Sun in September and passed within 15 million miles of Earth on October 15.

One of the most peculiar things about it was how fast it was moving. Covering 15.8 miles (25.5 km) each second, the super-fast space rock is so hot it almost looked red.
Breakthrough Listen decided to study the object, now named ‘Oumuamua, and didn’t find evidence for any alien activity.

Source: Wired