A newly released image shows the ‘light echoes’ from a briefly reignited black hole

Lord of the rings

CHANDRA X-RAY OBSERVATORY/PAN-STARRS/NEIL GEHRELS SWIFT OBSERVATORY, 5 AUGUST 2021

V404 Cygni became a short-lived celestial celebrity in 2015 when NASA’s Neil Gehrels Swift Observatory, a space observatory dedicated to scrutinising gamma-ray bursts, detected an unusual burst of X-rays coming from the constellation of Cygnus, the Swan.

The source was a black hole 7,800 lightyears away, waking up from its slumber. Suddenly the binary system became the focus of observatories worldwide as they watched it flare and sputter back to life after two decades in repose.

The high-intensity X-rays streaming out were the result of the black hole dragging material away from its companion star, then releasing jets of gas that formed a disc. As that heated to a million degrees V404 became an X-ray source 50 times brighter than the Crab Nebula, M1.

In this newly released image from the Chandra X-Ray Observatory we see the ‘light echoes’ created as those rays bounced off dust clouds around the black hole. The different apparent sizes of the concentric rings reveal their relative distances; rings appear larger if the cloud is closer to us, and vice versa.

Hello Venus

SOLAR ORBITER, 7–9 AUGUST 2021

These stills are taken from footage captured by the Heliospheric Imager aboard ESA/NASA’s Solar Orbiter as it sailed within 7,995km of Venus. The planet (looking like a crescent) approaches from the left while the Sun is off camera to the upper right. Venus’s night side appears dark and rounded, surrounded by a bright crescent of light: the glare from its sunlit side. The stars Omicron (o) Tauri and Xi (c) Tauri can be seen in the first image (top).

Under pressure

HUBBLE SPACE TELESCOPE/ALMA, 29 JULY 2021

Gases stripped from galaxies may re-accrete and delay their death, scientists believe. Barred spiral galaxy NGC 4921 seems in its death throes, buffeted by its galaxy cluster, the Coma Cluster. Red/orange streaks reveal the filament structures left behind as its gas is stripped away in a process called ram pressure stripping. Without gas, eventually no new stars will form. However, new research shows that some gas is falling back towards its host, continuing star formation and slowing the galaxy’s demise.

Pin-sharp planet

CURIOSITY MARS ROVER, 17 AUGUST 2021

NASA’s Curiosity rover has captured a high-resolution 360˚ view of the Martian surface. The rover, which has travelled 26km since it landed in Gale Crater in 2012, reveals the terrain with great clarity. Stitched together from 129 photos, the centre of the image is ‘Rafael Navarro Mountain’, named after the scientist Dr Rafael Navarro-Gonzalez, who died of COVID-19 earlier this year. See a full video tour at bit.ly/3BcxaCH.

Herculean effort

LOFAR, 18 AUGUST 2021

Supergiant elliptical galaxy Hercules A shoots out fast jets that grow stronger and weaker every few thousand years, according to new research. The study is one of a collection just published, using almost a decade’s worth of data gathered by the Low Frequency Array (LOFAR). The network of 70,000 small radio antennae across nine European countries gives astronomers a ‘lens’ that is effectively 2,000km wide, which recently produced the most detailed-ever radio image survey of galaxies at frequencies around the FM radio band.

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