Scientists who caused a global sensation when they announced the discovery of gravitational waves may have been fooled by bits of dust floating about in space.
Researchers at Harvard University called a press conference in March to reveal that they had spotted the cosmic signature of ripples in space left over from the spectacular expansion of the early universe. The dramatic claim was hailed as one of the most important scientific discoveries of the century and promised a new era of physics.
However, the findings, which some experts doubted from the off, have received a serious blow from researchers with the European Space Agency’s (ESA) Planck mission, who found that galactic dust could fully explain the observation.
“It’s certainly possible that the results can be explained purely by dust,” said Jo Dunkley, professor of astrophysics and a member of the Planck team at Oxford University. “Our work doesn’t rule out the possibility that they have gravitational waves, but there is dust in there and it seems to be higher than thought.”
Cosmologists on Harvard’s Bicep2 team got excited when they spotted a twist in the polarization of light picked up by their telescope at the South Pole. The distinctive twist can be caused by gravitational waves, which squeeze and expand space as they spread out, creating patches of hotter and cooler space. The existence of gravitational waves was predicted by Albert Einstein’s 1916 general theory of relativity.
Light can be twisted by other means. Cosmologists always knew that clouds of dust spewed from exploding stars can mimic the signature of gravitational waves. Space dust is heated up by starlight, but re-emits the radiation as infra-red light. This light gets twisted because dust particles align themselves with the huge magnetic field that stretches through the plane of the Milky Way.
The paper from the Planck team reveals how much polarized light could come from dust alone.
“People thought there might be very clean regions of space, but what we find is that there are no truly clean regions free of polarized dust emission. And that includes the Bicep field,” said George Efstathiou, head of the Cambridge Planck Analysis Centre. “The level of dust that we infer in the Bicep region, or in any other clean region of the sky, is important: it’s comparable to the signal that Bicep have detected.”
Efstathiou said the Planck team’s results did not rule out the Bicep2 findings, but made clear how much dust had to be accounted for.
Andrew Pontzen, a cosmologist at University College London, said the Planck paper added to the weight of evidence that seemed to be going against the Bicep result.
“What you can say for sure is that the original analysis was insufficient to say the signal is really there. It doesn’t mean for sure that they haven’t seen anything,” he said.
Republican US lawmakers on Friday criticized US President Joe Biden’s administration after sanctioned Chinese telecoms equipment giant Huawei unveiled a laptop this week powered by an Intel artificial intelligence (AI) chip. The US placed Huawei on a trade restriction list in 2019 for contravening Iran sanctions, part of a broader effort to hobble Beijing’s technological advances. Placement on the list means the company’s suppliers have to seek a special, difficult-to-obtain license before shipping to it. One such license, issued by then-US president Donald Trump’s administration, has allowed Intel to ship central processors to Huawei for use in laptops since 2020. China hardliners
A top Vietnamese property tycoon was on Thursday sentenced to death in one of the biggest corruption cases in history, with an estimated US$27 billion in damages. A panel of three hand-picked jurors and two judges rejected all defense arguments by Truong My Lan, chair of major developer Van Thinh Phat, who was found guilty of swindling cash from Saigon Commercial Bank (SCB) over a decade. “The defendant’s actions ... eroded people’s trust in the leadership of the [Communist] Party and state,” read the verdict at the trial in Ho Chi Minh City. After the five-week trial, 85 others were also sentenced on
Conjoined twins Lori and George Schappell, who pursued separate careers, interests and relationships during lives that defied medical expectations, died this month in Pennsylvania, funeral home officials said. They were 62. The twins, listed by Guinness World Records as the oldest living conjoined twins, died on April 7 at the Hospital of the University of Pennsylvania, obituaries posted by Leibensperger Funeral Homes of Hamburg said. The cause of death was not detailed. “When we were born, the doctors didn’t think we’d make 30, but we proved them wrong,” Lori said in an interview when they turned 50, the Philadelphia Inquirer reported. The
RAMPAGE: A Palestinian man was left dead after dozens of Israeli settlers searching for a missing 14-year-old boy stormed a village in the Israeli-occupied West Bank US President Joe Biden on Friday said he expected Iran to attack Israel “sooner, rather than later” and warned Tehran not to proceed. Asked by reporters about his message to Iran, Biden simply said: “Don’t,” underscoring Washington’s commitment to defend Israel. “We are devoted to the defense of Israel. We will support Israel. We will help defend Israel and Iran will not succeed,” he said. Biden said he would not divulge secure information, but said his expectation was that an attack could come “sooner, rather than later.” Israel braced on Friday for an attack by Iran or its proxies as warnings grew of