One of LIGO’s gravitational wave detectors Christian Offenberg / Alamy Stock Photo

LIGO is back at it. Having just turned back on after months of upgrades on 1 April, the Laser Interferometer Gravitational-Wave Observatory has already spotted another pair of black holes colliding.

Gravitational waves are ripples in space-time that occur whenever massive objects move, like the wake behind a boat travelling across a lake. LIGO announced the first-ever observations of gravitational waves in 2016 and has now spotted a total of 12 gravitational signatures of pairs of enormous objects smashing together.

Now that the twin detectors in Livingston, Louisiana, and Hanford, Washington, have been upgraded, we expect to see about one set of gravitational waves per week. And just one week after the detectors were turned back on, that expectation is already becoming reality with the detection of gravitational waves from a pair of merging black holes almost 5 billion light years away. LIGO made the find in collaboration with the Virgo gravitational wave observatory in Italy.

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LIGO and Virgo haven’t released any information on the sizes of the two black holes. But based on the strength of the signal from so far away, they are probably relatively large like several of the earlier detections, perhaps around 30 times the mass of the sun, says astronomer Derek Fox at Pennsylvania State University. “Just being big and loud and right at the beginning of the run is exciting,” he says.

Now, these marvels of general relativity have become almost commonplace, so much so that you can sign up to be alerted to each new detection via an iPhone app. The point of the public alerts is to let astronomers around the world know where to point their telescopes for follow-up observations, says Fox.

That will come in handy during this new set of observations, which is expected to last a year or more. “This observing run is supposed to bring a real harvest of black holes and also probably a few neutron stars,” says Fox. “Some of us have been looking forward to this new era for a long time.”</s>After more than a year-long hiatus, the Laser Interferometer Gravitational-Wave Observatory (LIGO) is back online and more sensitive than ever to the tiny ripples in spacetime generated when black holes and dead stars collide.

Following numerous upgrades to its lasers, mirrors, and quantum noise filters, LIGO—which consists of twin detectors in Washington and Louisiana—is now about 40 percent more sensitive to gravitational waves compared to its last run. This means that it can scan about twice the volume of space for smash-ups between two black holes or two neutron stars than before.

Working with its European counterpart, VIRGO, LIGO may even be able to detect gravitational waves from predicted, but as yet unseen, black hole-neutron star mergers.

Here, two longtime members of the LIGO group, Robert Byer and Brian Lantz, explain how the moon passing overhead or earthquakes on the far side of the Earth can disrupt LIGO. Byer, a professor at Stanford University, and Lantz, a senior research scientist, also recall how the first detection of a gravitational wave in 2015 was met with widespread skepticism and discuss plans for LIGO’s future.</s>It's a change of strategy for Samsung. The South Korean manufacturer has confirmed the discontinuation of its Galaxy J range. It will now be replaced by the most affordable smartphones in its Galaxy A category.

The announcement of many new devicesin the Galaxy A range (Galaxy A10, Galaxy A20, Galaxy A30, Galaxy A40, Galaxy A50 and Galaxy A70) was no accident. The world's number one has reorganized its catalog.

In a video published by Samsung Malaysia, the manufacturer explains that the Galaxy Js are now the Galaxy As. This category offers more features, such as dual and triple cameras or the presence of a fingerprint reader under the screen, but also offers more power. The Galaxy A30 and A50 are therefore the ambassadors of this new range. Other new features are expected to be announced by the manufacturer this week, including the official launch of the Galaxy A90.
• Samsung Galaxy A50 & A30: blurring the lines between flagship and mid-range
LIGO and Virgo detect a gravitational wave from a galaxy 6 billion light-years away in the direction of Cassiopeia, with further details being released on April 10.