BERLIN: A team of international scientists observing a star in the Milky Way have for the first time confirmed Einstein’s predictions of what happens to the motion of a star passing close to a supermassive black hole.
Einstein’s 100-year-old general theory of relativity predicted that light from stars would be stretched to longer wavelengths by the extreme gravitational field of a black hole, and the star would appear redder, an effect known as gravitational red shift.
“This was the first time we could test directly Einstein’s theory of general relativity near a supermassive black hole,” Frank Eisenhauer, senior astronomer at the Max Planck Institute for Extraterrestrial Physics, told journalists.
“At the time of Einstein, he could not think or dream of what we are showing today,” he said.
A team of scientists at the European Southern Observatory started monitoring the central area of the Milky Way using its Very Large Telescope to observe the motion of stars near the supermassive black hole 26 years ago.
The black hole is 26,000 light years away from Earth and has a mass 4 million times that of the Sun.
The scientists selected one star, S2, to follow. With an orbit of 16 years, they knew it would return close to the black hole in 2018.
Over 20 years, the accuracy of their instruments has improved and so in May 2018, they were able to take extremely precise measurements in conjunction with scientists from around the world.
This showed the star’s orbital velocity increasing to more than 25 million kph (15.5 million mph) as it approached the black hole.
The star’s wavelength stretched as it sought to escape the gravitational pull of the supermassive black hole, shifting its appearance from blue to red, Odele Straub from the Paris Observatory said.
The scientists now hope to observe other theories of black hole physics, she said.
“This is the first step on a long road that the team has done over many years and which we hope to continue in the next years,” MPE’s Reinhard Genzel, who led the international team, said.
Scientists confirm Einstein’s supermassive black hole theory
Scientists confirm Einstein’s supermassive black hole theory
- The black hole is 26,000 light years away from Earth and has a mass 4 million times that of the Sun
- This showed the star’s orbital velocity increasing to more than 25 million kph (15.5 million mph) as it approached the black hole
Apple to update EU browser options, make more apps deletable
- iPhone maker came under pressure from regulators to make changes after the EU’s sweeping Digital Markets Act took effect on March 7
- Apple users will be able to select a default browser directly from the choice screen after going through a mandatory list of options
STOCKHOLM: Apple will change how users choose browser options in the European Union, add a dedicated section for changing default apps, and make more apps deletable, the company said on Thursday.
The iPhone maker came under pressure from regulators to make changes after the EU’s sweeping Digital Markets Act took effect on March 7, forcing big tech companies to offer mobile users the ability to select from a list of available web browsers on a “choice screen.”
The new rules require mobile software makers to show the choice screen where users can select a browser, search engine and virtual assistant as they set up their phones, which earlier came with preferred options from Apple and Google.
In an update later this year, Apple users will be able to select a default browser directly from the choice screen after going through a mandatory list of options.
A randomly ordered list of 12 browsers per EU country will be shown to the user with short descriptions, and the chosen one will be automatically downloaded, Apple said. The choice screen will also be available on iPads through an update later this year.
Apple released a previous update in response to the new rules in March, but browser companies criticized the design of its choice screen, and the Commission opened an investigation on March 25 saying it suspected that the measures fell short of effective compliance.
The company said it has been in dialogue with the European Commission and believes the new changes will address regulators’ concerns.
It also plans to introduce a dedicated area for default apps where a user will be able to set defaults for messaging, phone calls, spam filters, password managers and keyboards.
Users will also be able to delete certain Apple-made apps such as App Store, Messages, Camera, Photos and Safari. Only Settings and Phone apps would not be deletable.
