Core Insights - A record-breaking gamma-ray burst (GRB 250702B) occurred on July 2, 2025, lasting over 29 hours, challenging traditional understanding of gamma-ray bursts and prompting global astronomical investigation [5][6] - The event is believed to involve a medium-mass black hole tearing apart and consuming a white dwarf star, as proposed by the research team from the Chinese Academy of Sciences [6][8] Group 1: Event Details - The gamma-ray burst was detected by the Fermi Gamma-ray Space Telescope and was initially named GRB 250702D, later unified under the name GRB 250702B after confirming it originated from the same high-energy source [6][7] - This gamma-ray burst is noted for being the longest known, with energy release equivalent to that of 1,000 suns burning for 10 billion years, which significantly alters the understanding of such cosmic events [6][8] Group 2: Scientific Explanations - The "Tian Guan" satellite's research team proposed a model where a medium-mass black hole, between hundreds to hundreds of thousands of solar masses, uses tidal forces to disrupt and consume a dense white dwarf star [8][9] - Alternative theories suggest the event could be due to a supernova collapse model, where a massive supernova's core collapses into a black hole, leading to relativistic jets that produce gamma-ray emissions [9][10] - Another hypothesis involves a stellar-mass black hole interacting with a helium star, leading to the formation of an accretion disk and subsequent gamma-ray emissions [10][11]

Core Viewpoint - The "Tian Guan" satellite (Einstein Probe Satellite) has captured an unprecedented high-energy cosmic explosion, which is believed to be the process of a medium-mass black hole tearing apart a white dwarf star, as reported in the academic journal "Science Bulletin" [1][2]. Group 1: Event Details - The "Tian Guan" satellite detected an exceptionally bright and rapidly changing X-ray source, designated "EP250702a," on July 2, 2025 [1]. - Following the detection, multiple global telescopes conducted a coordinated observation, confirming the source's location at the outskirts of a galaxy with a redshift of 1.04 [1]. - The "WXT" (Wide Field X-ray Telescope) and "FXT" (Follow-up X-ray Telescope) on the "Tian Guan" satellite played crucial roles in the observation, with the brightness of the event decreasing over ten days by more than 100,000 times after an intense explosion lasting about one day [1]. Group 2: Scientific Implications - The event "EP250702a" exhibited a series of unconventional characteristics, including multiple explosions from billions of light-years away, emitting extremely high energy, and rapid, complex changes in brightness and energy spectrum [2]. - The observed phenomena resemble rare black hole tidal disruption events, suggesting that a medium-mass black hole is involved in the process of tearing apart a white dwarf star, which is a dense celestial body [2]. - This event may provide the first clear evidence of such processes, aiding in the understanding of the long-missing population of medium-mass black holes and opening new avenues for research in black hole growth and the ultimate fate of dense celestial objects [2].

Core Insights - The "Tian Guan" satellite (Einstein Probe Satellite) captured an unprecedented high-energy cosmic explosion, which exhibits significant differences in brightness variation, radiation rhythm, and spectral characteristics compared to any known explosions [1][2] - The event, designated as "EP250702a," was observed on July 2, 2025, and involved a bright and rapidly changing X-ray source, leading to a global collaborative observation effort [1] Summary by Sections - **Event Characteristics** - The explosion occurred billions of light-years away, displaying multiple bursts of high energy with rapid and complex changes in brightness and energy spectrum, which cannot be fully explained by existing astronomical event models [2] - The rapid decay in brightness, dropping over 100,000 times within twenty days, suggests the involved celestial body is a dense white dwarf, indicating a medium-mass black hole tearing apart and consuming it [2] - **Scientific Implications** - This event may provide the first clear evidence of such a process, aiding in the understanding of medium-mass black holes, their growth, the ultimate fate of dense celestial bodies, and opening new avenues in multi-messenger astronomy [2]