APSARA was the first research reactor in Asia to reach criticality when it did so on August 4, 1956. It was a pool-type reactor with a 1 MW output that used 4.5 kg of highly enriched uranium in the form of plates as fuel. Both the moderator and the coolant were made of light water.

Arbaaz Khan is an Indian actor, director, and producer best known for his work in Hindi-language movies. He was born on August 4, 1967. In addition, he has appeared in a few television shows and films in the Urdu, Telugu, and Malayalam languages.

Phoenix was an unmanned space probe that landed on Mars on May 25, 2008 and operated until November 2, 2008. It was released on August 4, 2007. Phoenix operated on Mars for 157 sols (161 days). Its instruments were used to assess the local habitability of Mars and to investigate the history of water on the planet. The mission was part of the Mars Scout Program, and its total cost, including launch costs, was $420 million.

On August 4, 1958, Billboard debuted the Hot 100, an all-genre singles chart. The Hot 100 quickly became the industry standard, and on October 13, 1958, Billboard discontinued the Best Sellers In Stores chart.

Genelia Deshmukh, an Indian actress and model born on August 5, 1987, is most frequently seen in Telugu, Hindi, and Tamil movies. D'Souza launched her acting career in 2003 with the commercial success Tujhe Meri Kasam after becoming well-known for her appearance in a Parker Pen commercial with Amitabh Bachchan. The same year, she received praise for her work in Boys.

On August 5, 1914, the world's first electric traffic signal is installed at the intersection of Euclid Avenue and East 105th Street in Cleveland, Ohio. The first traffic signal consisted of four pairs of red and green lights mounted on corner posts to serve as stop-go indicators. It was connected to a manually operated switch inside a nearby control booth, and the system was designed to prevent conflicting signals.

American Meghan, Duchess of Sussex (born August 4, 1981), a former actress, is a member of the British royal family. Markle grew up in Los Angeles, California, where she was born. At Northwestern University, she began her acting career; her final and most notable on-screen performance was as Rachel Zane for seven seasons (2011–2018) in the American TV legal drama Suits.

Ambi Subramaniam is a violinist, composer, and educator who was born in Los Angeles, California, on August 5, 1991. He began giving stage performances when he was six years old, and the Times of India dubbed him the "new king of Indian classical violin." The Ozy Magazine referred to him as "India's 24-year-old Itzhak Perlman."

Indian playback singer and actor Kishore Kumar was born on 4 August 1929 and passed away on 13 October 1987. He is regarded as one of the greatest and most versatile singers in Indian music history. He was one of the most well-known singers in the Indian film industry and was well-known for his yodelling and versatility.

American astronaut and aeronautical engineer Neil Alden Armstrong, who died on August 25, 2012, was the first person to set foot on the moon. He was born on August 5, 1930. In addition, he was a test pilot, university professor, and naval aviator. Ohio's Wapakoneta is where Armstrong was born and raised. He was a Purdue University graduate who majored in aeronautical engineering. The U.S. Navy funded his college education through the Holloway Plan.

Indian actress Kajol Devgn, better known by her stage name Kajol, was born on August 5, 1974. She has received numerous honours, including six Filmfare Awards, where she shares the record for most Best Actress wins with her late aunt Nutan. She has been hailed as one of the most successful actresses in Hindi film. She received the Padma Shri award from the Indian government in 2011.

A resolution to revoke the temporary special status, or autonomy, granted to Jammu and Kashmir under Article 370 of the Indian Constitution was approved by the Indian Parliament on August 5, 2019. Jammu and Kashmir is a region administered by India as a state that is made up of the larger portion of Kashmir, which has been the subject of a dispute between India, Pakistan, and China since 1947.

Indian film director, screenwriter, producer, music composer, and playback singer Vishal Bhardwaj was born on August 4, 1965. He has won seven National Film Awards in four categories and is well known for his work in Hindi film.

Nelson Rolihlahla Mandela, a South African anti-apartheid activist who presided over South Africa from 1994 to 1999, was born on July 18, 1918, and passed away on December 5, 2013. Police apprehended Mandela and fellow activist Cecil Williams on August 5, 1962, close to Howick.

Barack Hussein Obama, an American politician born on August 4, 1961, led the country as its 44th president from 2009 to 2017. He served as the country's first African-American president. He was a Democrat and previously held the offices of Illinois state senator from 1997 to 2004 and U.S. senator from Illinois from 2005 to 2008.

Neil Armstrong was an American astronaut and aeronautical engineer who was the first person to walk on the Moon. He was born on August 5, 1930. He was also a naval aviator, test pilot, and university professor. Armstrong, Edwin E. Aldrin, Jr., and Michael Collins launched the Apollo 11 spacecraft toward the Moon on July 16, 1969.