Scientists recently produced the first real image of a black hole, in a galaxy called Messier 87. The image is not a photograph but an image created by the Event Horizon Telescope (EHT) project. Using a network of eight ground-based telescopes across the world, the EHT collected data to produce the image. The black hole itself is unseeable, as it’s impossible for light to escape from it; what we can see is its event horizon. The EHT was also observing a black hole located at the centre of the Milky Way, but was unable to produce an image. While Messier 87 is further away, it was easier to observe, due to its larger size.
The golden ring is the event horizon - the moment an object approaching a black hole reaches a point of no return, unable to escape its gravitational pull. Objects that pass into the event horizon are thought to go through spaghettification, a process, first described by Stephen Hawking, in which they will be stretched out like a piece of pasta by gravitational forces.
According to some professors, the image shows a silhouette of the hole against the surrounding glow of the event horizon, all of the matter being pulled into the hole. At the centre of the black hole is a gravitational singularity, where all matter is crushed into an infinitely small space.
The black hole lies 55m light years away from us. It is around 100bn km wide, larger than the entire solar system and 6.5bn times the mass of our sun.
Through creating an image of a black hole, something previously thought to be impossible, the EHT project has made a breakthrough in the understanding of black holes, whose existence has long been difficult to prove. The image will help physicists to better understand how black holes work and images of the event horizon are particularly important for testing the theory of general relativity.
Plastic pollution is a devastating problem for the world’s oceans and marine life. According to the UN, about 8m tonnes of plastic waste is dumped in the seas annually.
While the ultimate goal is to stop plastics from entering the water in the first place, cleanup projects play an important role. Seabin Project - plastic-cleaning devices deployed in harbours and marinas - is one.
Water is sucked in from the surface and passes through a catch bag inside the Seabin, with a submersible water pump capable of displacing 25.000 Lph (litres per hour), plugged directly into either a 110V or 220V outlet. The water is then pumped back into the marina leaving litter and debris trapped in the catch bag.
The Seabin can catch an estimated 3.9 kgs of floating debris per day or 1.4 tons per year (depending on weather and debris volumes) including micro plastics down to 2 mm small.
There are 450 Seabins in 26 countries around the world, in 60 harbours throughout the US, Europe, and now the Asia-Pacific, collecting on average around 4kg of marine litter a day - or about 1.4 tonnes a year.
Compiled by SG