Chinese and foreign astronomers have achieved a breakthrough in dark energy research, offering fresh insights into the physical mechanisms behind the accelerated expansion of the universe. The findings, announced by the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) on Wednesday, suggest potential new physics beyond the standard cosmological model. Dark energy remains one of the most profound mysteries in modern physics. Since the discovery of accelerated cosmic expansion in the late 1990s, scientists have attributed this phenomenon to an enigmatic cosmic component called dark energy. Yet its true nature remains a mystery. The standard cosmological model interprets dark energy as a static vacuum energy. While successfully explaining a large number of cosmological observations for over two decades, recent advancements in observational precision have exposed inconsistencies among different datasets under this framework, challenging its completeness and opening avenues for alternative theories. Leading this quest is the Dark Energy Spectroscopic Instrument (DESI), a global collaboration involving over 70 institutions. Utilizing a four-meter optical telescope, DESI maps the universe's 3D large-scale structure by measuring redshifts of tens of millions of celestial objects. The Galaxy Survey and Cosmology Group at NAOC, led by Zhao Gongbo, and the Wide-field Survey and Galaxy Physics Group at NAOC, led by Zou Hu, have been involved in the DESI project for over a decade. In the latest study, Zhao's team, leading the DESI collaboration, has achieved significant breakthroughs in the dynamical properties of dark energy. By employing a novel methodology independently developed by the researchers, the team conducted an in-depth analysis of the latest cosmological distance measurements from DESI observations, combined with data from supernovae and cosmic microwave background radiation. Their findings revealed that the equation of state for dark energy changes as the universe evolves. This result confirms the previous conclusion of the DESI collaboration derived through distinct analytical approaches, that dark energy is likely to have dynamic properties. The conclusion implies that dark energy may not be a constant vacuum energy, but rather exhibits more complex evolutionary behavior. The study not only pioneers new research pathways for unraveling the physical essence of dark energy, but also provides pivotal clues for constructing a more comprehensive theoretical framework in cosmology.
"The standard cosmological model suggests that dark energy is the vacuum energy proposed by Einstein over a century ago. Like vaccum energy, dark energy was assumed to be constant over time. However, we have found evidence that dark energy evolves over time, disproving the idea that vacuum energy could be a form of dark energy. Such a discovery would represent a revolutionary breakthrough in fundamental physics," said Zhao.
DESI, managed by the U.S. Department of Energy's Lawrence Berkeley National Laboratory, involves more than 900 researchers from 70 institutions worldwide.
Astronomers' dark energy breakthrough sheds new light on cosmic accelerated expansion
The Shenzhen Science and Technology Museum in south China's Guangdong Province has received over four million visitors since opening on May 1 last year.
In addition to gaining astounding popularity, the museum has been selected as one of the "World's Most Beautiful Museums" by UNESCO.
One morning during the first anniversary period of its opening, the museum was already packed with student groups and family visitors as early as 10:00.
To the delight of the hundreds of children attending on that day, the museum is filled with highly interactive exhibits that are as fun as they are educational. In the AI ping-pong robot zone, visitors play matches against a robot, which adjusts its difficulty level in real time according to human opponent's skill, precisely matching ball speed and strength.
"I tried seven or eight exhibits. My favorite is the ping-pong. The experience showed me how powerful science can be, and the ping-pong robot made me realize that machines can be so amazing," said Mo Jiquan, a young student from Guangdong's Zhongshan City.
In the "Smart Industry" hall, a group of students from Singapore learned to race model cars controlled by brainwaves.
By pressing foreheads against an electroencephalogram (EEG) signal collection device and concentrating, the students used the power of their minds to propel the cars forward.
"Science fiction has become reality. These things are different from what we learn at school. For example, these brainwave-control devices, we have never seen anything like them. So I think it's a new and very meaningful experience," said Chen Mengfanglin, a student from Singapore.
Among the museum's 950 innovative exhibits, such as brain-computer interfaces, simulated space capsules, dexterous hands, 80 percent offer deep interactive experiences.
More importantly, these exhibits are dynamically updated as industrial technologies evolve.
"I think this place is very futuristic and fun. This is my second time here. I feel that there are more exhibits, and the technology has advanced," said Wu Zining, a Shenzhen student.
According to the museum, visitor numbers remain steady on weekdays, surge significantly during holidays, and overseas visitors have seen a notable increase since the beginning of this year.
"Our museum receives between 2,000 and 5,000 visitors on weekdays. On holidays, we get around 30,000 visitors per day. Since the beginning of this year, the number of overseas visitors has also risen significantly," Zhang Haitian, director of the Exchange and Cooperation Center of the museum.
Unlike traditional science museums that simply display items alongside written explanations, the Shenzhen Science and Technology Museum has pioneered an approach that combines innovation, public outreach, and education into one seamless experience.
Over the past year, it has collected 39 technology transfer projects, held 10 "deep science and technology" project matchmaking events, and brought research institutes, leading enterprises, investors, and the public together, creating a new ecosystem linking government, enterprises, research institutes, and the museum.
"On the basis of the original basic functions of a science and technology museum, we have taken a bolder step forward. We have extensive links with sci-tech innovation companies, so a steady stream of new technologies, achievements, products and ideas flow into the museum. We also have close interactions with science fiction and cultural heritage sectors, integrating science and technology with culture and art. Through flexible cooperation with various industries, this approach has opened up unlimited possibilities for the entire science and technology museum," said Zheng Yongchun, head of the museum.
Interactive sci-tech museum in south China hosts 4 million visitors in first year
