The bright side of black holes

Over a billion years ago, two black holes in a distant galaxy spiralled together, rippling the very fabric of space. In December, those ripples reached the Laser Interferometer Gravitational‑Wave Observatory (LIGO) in the US, marking the second gravitational wave detection in history. The first occurred just three months before.

Black holes are real, and they’re speaking to us directly from across the cosmos.

In popular culture, a black hole is the ultimate metaphor for an invisible destroyer: a dark, inescapable force swallowing everything in its path. Not even light can escape its gravitational pull. Yet black holes are some of the most essential, ubiquitous and brightest objects in the universe.

Black holes were first proposed as a natural result of the death of a star. Now there are hints that black holes might also be an essential part of the formation and evolution of galaxies.

Our own galaxy is teeming with black holes – hundreds of millions according to one estimate. The simplest way to make a black hole is to take a star many times as massive as the Sun and wait several million years for it to run out of fuel. When that happens, it will collapse in on itself.

To a physicist, a black hole is fairly simple: a pure spacetime object defined only by its mass, spin (leftover from the spin of the progenitor star), and perhaps an electric charge. According to a yet‑to‑be‑proven theorem, black holes cannot have any other properties. From an astronomer’s point of view, however, black holes are anything but simple.

Astronomers are still working to understand exactly how supermassive black holes in the centres of galaxies grow to such enormous sizes, but it seems clear that the growth of black holes and the growth of galaxies are inextricably linked.

Even though a supermassive black hole constitutes a tiny fraction of a galaxy’s total mass, the two appear to build up in lockstep with each other. How one manages to influence the other is still a mystery.

Black holes are far more than just a cool abstract concept about the stretching of time and the “spaghettification” of things that fall in. They are central to the evolution and structure of the cosmos. And we’re just starting to explore how.

When giants warped the universe

They gobble stars, bend space, warp time and may even provide gateways to other universes.

Black holes fire the imagination of scientists and science-fiction aficionados alike. But at least one thing about them wasn’t all that mind-bending: we’ve long understood black holes to be the end point in the life of a big star, when it runs out of fuel and collapses on itself.

However, in recent times astronomers have been confronted with a paradox: gigantic black holes that existed when the universe was less than a billion years old.

Since average-sized black holes take many billions of years to form, astrophysicists have been scratching their heads to figure out how these monsters could have arisen so early. It now seems that rather than being the end game in the evolution of stars and galaxies, supermassive black holes were around at their beginnings and played a major role in shaping them.

The first accurate description of black holes came in 1916 from German physicist and astronomer Karl Schwarzschild. Schwarzschild was serving in the German Army at the time, despite already being over 40 years of age.

After seeing action on both the western and eastern fronts, Schwarzschild was sent home due to a serious auto-immune skin disease, pemphigus.

It was late 1915 and Einstein’s theory of General Relativity had just been published. Inspired, Schwarzschild lost no time writing a paper that predicted the existence of black holes; it was published just months before he succumbed to his disease in May 1916.

According to Einstein’s theory, the force of gravity was the result of a mass distorting the fabric of space-time. In the same way that a bowling ball dimples the fabric of a trampoline, a star’s mass dimpled the space-time fabric of its system, keeping planets circling around it.

The first evidence that black holes weren’t just theoretical came in 1964, when a rocket decked with sensitive instruments was shot into sub-orbital space. It detected suspicious X-rays emanating from the constellation of Cygnus (the swan).

The X-ray source became known as Cygnus X-1. By the early 1970s most astronomers inferred the X-rays were radiated by super-heated matter being sucked into the gravitational field of the black hole. It would take decades more, however, before the first conclusive evidence that black holes exist and obey Einstein’s equations of general relativity.

This came in September 2015 with the detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States. These ripples in the fabric of space-time had been generated by two black holes colliding 1.3 billion years ago. Theorists had predicted that if such a titanic event occurred somewhere in our galaxy, the reverberations should be measurable on Earth.

LIGO’s detection of gravitational waves thus also confirmed the existence of black holes. Yet even as the evidence that black holes truly exist has firmed up, our understanding of how they arise seems to be crumbling.

“The growth of black holes seems to be a crucial element in galaxy formation,” Begelman agrees. “Galaxies would look very different if there weren’t these black holes.”

Of course, the absolute proof that direct collapse black holes exist will come when one is observed.

In the past year astronomers have seen some tantalising clues. One is a galaxy known as CR7, which hosts a source of light much brighter than its stars – perhaps the radiation caused by a black hole sucking in gas.

“You see evidence for a galaxy that has mainly hydrogen and helium,” Loeb says. “That could potentially be the birthplace of a direct collapse black hole.”

What we have learnt by exploring Mars

The Schiaparelli probe made headlines in October 2016 when it crash-landed on Mars. It wasn’t a disaster, though, it was mainly a practice run for the European Space Agency’s next mission to the red planet: delivery of a craft bearing the science station and rover, scheduled for 2020. The main game of the Schiaparelli probe – the “ExoMars” mission – was to deploy the mothership, the 13th of an international fleet of ships spying on Mars. Known as the Trace Gas Orbiter (TGO), its goal is to sniff out methane, a potential signature of life. The gas has been detected by previous orbiters, the Curiosity Rover and Earth-based telescopes. But where the plumes came from was impossible to say. TGO’s instruments will pinpoint the source with a thousand-fold greater accuracy than ever before.

Follow the water

In September 2015, NASA’s Mars Reconnaissance Orbiter had a better reason to grab headlines: it found evidence of flowing water. MRO’s spectrometer showed that dark streaks on the slopes of some craters and canyons were composed of salts left by evaporating water. It also identified clay sediments on a canyon floor in the Nili Fossae region, a candidate site for a future landing mission…

… Two older orbiters, the 2001 Mars Odyssey and Mars Global Surveyor, identified ancient lakes and snowmelt-fed streams in the Arabia Terra region (white represents lowest elevation, yellow highest). Based on the number of craters, scientists estimate they held water until 2-3 billion years ago – a billion years later than previously thought.

Stolen by the Sun

So what happened to Mars’ ancient lakes and streams?

In November 2015, NASA’s MAVEN (Mars Atmosphere and Volatile Evolution Mission) orbiter revealed the answer: the solar wind blew away most of the atmosphere. Without its protective blanket, the planet’s water evaporated.

Dipping into the thin Martian atmosphere, just 1% as thick as Earth’s, MAVEN measured wisps of ionised gas streaming away from the planet at a rate of 100 grams per second. The rate increased 20-fold when a solar storm struck. That’s shown in this simulated image: white streaks are the solar wind and the coloured streaks show the energy of escaping Martian gases. The hottest colours have the highest energy and are concentrated at the pole.

Gravity map

Mars is pockmarked by towering mountains such as Olympus Mons – three times the height of Mount Everest – and craters 9 km deep. The mass differences in the crust mean spacecraft experience tiny changes in gravitational tug as they orbit Mars. These wobbles are measurable and can be used to calculate the changing gravity and mass. For instance, they revealed that the mass of the CO₂ icecaps varies seasonally by 4 trillion tons.

Scientists pooled measurements from three orbiters to build this gravity map of the planet in 2016. Low-gravity canyons like Valles Marineris in blue (centre) stand out from the high-gravity reds and whites of Tharsis Montes, the three aligned volcanoes left of centre and Olympus Mons, above and left. This ‘gravity’ map will help future craft chart their orbit with greater precision.

Credit: NASA’s Scientific Visualization Studio

Why does the universe smell so bad?

Smell is perhaps our most mysterious sense.

It can trigger memories and link us to specific times and places. It’s not surprising that we often wonder what distant and exotic places would smell like, from the frequent mention of odour in Gulliver’s Travels to Professor Farnsworth’s Smell-O-Scope in Futurama.

So, setting aside the practical problems of trying to take a lungful of vacuum, what would it be like to get a whiff of the sparse gases and particles that occupy deep space?

If we turn our nose to Sagittarius B2, a cloud of gas about 390 light years from the centre of the Milky Way, we would encounter a host of olfactory delights. Almost every chemical that has been detected in space can be found there.

Among the smellier components of Sagittarius B2 is hydrogen sulfide (H₂S), often described as rotten-egg gas.

This chemical can be detected at around 10 billion molecules per cubic centimetre by the human nose, and can cause death in high concentrations. At its most dense, the Sagittarius cloud contains only about one million molecules per cubic centimetre, about 10,000 times beneath the human threshold.

We might also encounter hydrogen cyanide (HCN), another deadly gas, though this one smells of bitter almonds. Chemists in the early twentieth century used to smoke cigarettes while working with this chemical, because a release of hydrogen cyanide would change the flavour of the tobacco and act as an early warning sign of a leak.

There are also much more agreeable odours in space. Ethyl formate belongs to a class of molecules called esters, which often have sweet and fruity aromas. It is one of the chemicals responsible for the smell of raspberries.

Space is also home to compounds called polyaromatic hydrocarbons, flat molecules made up of rings of carbon atoms. These chemicals were named “aromatic” by early chemists before their structure was known, due to the strong smells they produce.

Their fragrances range from faintly pleasant to the strong smell of coal tar. A study just published in The Astrophysical Journal found they are present in much higher concentrations than previously throught, especially in older galaxies.

The main difference between the gases of space and those in our own atmosphere is the abundance of oxygen on earth, meaning that many smelly chemicals based on sulfur or phosphorus exist here in their milder, oxidised forms. So taking a deep whiff of space gas would probably smell closest to rotting garbage, fish, or flatulence.

NASA Plans to Build Moon-Orbiting Spaceport

NASA is planning to establish a crewed spaceport near the Moon that could serve as a gateway to the lunar surface and deep space destinations including Mars. The area of space near the Moon offers a true deep space environment to gain experience for human missions that push farther into the solar system, access the lunar surface for robotic missions but with the ability to return to Earth if needed in days rather than weeks or months, NASA said.

The period of exploration in the vicinity of the Moon will begin with the first integrated mission of the Space Launch System (SLS) rocket and the Orion spacecraft, it said. The agency is looking to build a crew tended spaceport in lunar orbit within the first few missions that would serve as a gateway to deep space and the lunar surface.

This deep space gateway would have a power bus, a small habitat to extend crew time, docking capability, an airlock, and serviced by logistics modules to enable research. The propulsion system on the gateway mainly uses high power electric propulsion for station keeping and the ability to transfer among a family of orbits in the lunar vicinity.

The three primary elements of the gateway, the power and propulsion bus and habitat module, and a small logistics module(s), would take advantage of the cargo capacity of SLS and crewed deep space capability of Orion. An airlock can further augment the capabilities of the gateway and can fly on a subsequent exploration mission.

„The gateway could move to support robotic or partner missions to the surface of the Moon, or to a high lunar orbit to support missions departing from the gateway to other destinations in the solar system,“ said William Gerstenmaier, associate administrator for Human Exploration and Operations at NASA.

The second phase of missions will confirm that the agency’s capabilities built for humans can perform long duration missions beyond the Moon.

For those destinations farther into the solar system, including Mars, NASA envisions a deep space transport spacecraft. This spacecraft would be a reusable vehicle that uses electric and chemical propulsion and would be specifically designed for crewed missions to destinations such as Mars.

The transport would take crew out to their destination, return them back to the gateway, where it can be serviced and sent out again.

Russia Seeks New Cosmonauts for Manned Mission to Moon in 2031

Russia’s space agency on Tuesday announced a recruitment drive for young would-be cosmonauts who it hopes will become the country’s first on the Moon. And women are welcome, an official stressed.

In the first such drive for five years, Roscosmos space agency said it is looking for 6 to 8 cosmonauts who will operate a new-generation spaceship now in development and „will become the first Russians to fly to the Moon“.

Russia is keen to rekindle the space triumphs of the Soviet era after a series of embarrassing glitches in recent years.

It has announced plans for its first manned Moon landing by 2031.

„There will be no discrimination based on skin colour or gender,“ the executive director of manned programmes Sergei Krikalyov said at a news conference, quoted by RIA Novosti news agency.

Applications are welcome for the next four months, said the first deputy director of Roscosmos Alexander Ivanov, cited by RIA Novosti.

Ivanov said the new recruits will pilot the first launches of the new-generation Federatsiya manned transport ship and „continue the lunar programme“.
The Federatsiya is designed to fly to the Moon with four people on board. The first manned test launch is planned in 2023 from Russia’s new Vostochny cosmodrome in the country’s far east.

The criteria for applicants include an age limit of 35, height between 1 metre 50 centimetres and 1 metre 90 (4 foot, 11 inches to 6 foot, 2 inches) and weight of no more than 90 kilograms (14 stone, 2 pounds), according to Roscosmos.

IT skills and knowledge of a foreign language are required as well as an engineering degree or pilot training or experience in the aviation or space industries.

A high standard of fitness is a must and would-be astronauts have to cross-country ski for 5 kilometres. They undergo a barrage of psychological and physical tests including gynaecological examinations for women.

Applicants can apply by post or in person to Star City astronaut training centre outside Moscow, remembering to enclose three passport-sized photographs.

Russia currently has 30 cosmonauts, 14 of whom have never been in space. The oldest is 58-year-old Gennady Padalka, who holds the world record for total time spent in space, while the youngest is 31-year-old Ivan Vagner, according to TASS state news agency.

The first such open recruitment drive – not just for military pilots and those working in the space industry – was held in 2012.

Jupiter at Opposition and the Lyrid Meteor Shower in April 2017 Skywatching

Jupiter will shine bright and appear large on April 7 as it reaches opposition. The moon will be nearly in its New moon phases during the peak of the Lyrid meteor showers making skywatching conditions optimal. Also, the meteor shower will radiate thought the “Summer Triangle” of stars.

 

James Webb Space Telescope Can Unlock Mysteries of TRAPPIST-1

NASA’s James Webb Space Telescope (JWST ) is currently being tested ahead of its scheduled 2018 launch. NASA astrophysicist Amber Straughn updates Space.com’s Sarah Lewin on where they are with the testing and what she hopes we can learn about the Universe from the Hubble Space Telescope’s scientific successor.

Spacewalk ‘Hyperlapse’ – ESA Astronaut Checks Space Station For Leaks

Astronaut Thomas Pesquet checked the cooling system for leaks on March 24, 2017 and took pictures of pipes for further analysis. No issues were immediately detected.

Epic Cassini Saturn Mission Begins ‘Grand Finale’ This Month

PASADENA, Calif. — NASA’s veteran Cassini mission will officially kick off its farewell tour of the Saturn system on April 22 with a final close encounter of the ringed planet’s largest moon, Titan. Five months later, on Sept. 15, Cassini will spectacularly burn up in Saturn’s crushing atmosphere.

But before that happens, Cassini will dive through a 1,200-mile (1,930 kilometers) gap between the planet and its innermost ring to carry out science that is only possible now that the mission is running out of fuel.

The „Grand Finale“ will begin when Titan’s gravity hurls the spacecraft close to Saturn’s atmosphere, ending the probe’s series of ring-grazing orbits and causing Cassini to dive through a gap in the rings.

Over the next 22 orbits between the planet and the innermost ring, Cassini will embark on a completely different phase of discovery. The spacecraft will carry out scientific measurements of the apparently empty environment between the planet’s upper-atmosphere gases and the innermost edge of Saturn’s D-ring.

„The Grand Finale is a brand-new mission,“ said Linda Spilker, Cassini project scientist at JPL. „We’re going to a place that we’ve never been before … and I think some of the biggest discoveries may come from these final orbits.“

Since arriving in Saturn orbit in 2004, Cassini has steered clear of the planet’s icy ring material, opting for a more distant (and safer) orbit where the gas giant’s family of moons could be studied and Saturn could be observed from afar. But now that the mission is in its final months, more risks can be taken to carry out observations that scientists would have only dreamed of earlier in the mission. During the daring ring dives, Cassini will be closer to the planet than ever before. The probe will use its mass spectrometer to „taste“ the chemistry of the tenuous gases on the outermost edge of Saturn’s atmosphere and return the most detailed observations ever obtained of Saturn’s high-altitude clouds and ring material.

Cassini also discovered Enceladus’ amazing water plumes, which in turn helped reveal that the satellite hosts an ocean of liquid water beneath its icy shell. And the probe has imaged Saturn’s diverse family of moons in detail that was not possible before.

Cassini has been a decades-long odyssey for the scientists involved, and the probe’s 3-minute final dive into Saturn’s atmosphere on Sept. 15 will be a bittersweet moment, the researchers said.

„I think that once the signal is lost, it would mean the heartbeat of Cassini is gone,“ said Spilker. „I think there will be a tremendous cheer and applause for the completion of an absolutely incredible mission. Hugs, tears — the Kleenex box will be passed around — but we will rejoice at being part of such a wonderful mission.“