At around 4am on July 15, people in Quang Ngai, Da Nang... saw a strange object flying in the sky. Seeing it strange, many people took photos and filmed and posted it on social media with many questions about what this object was.
On the same morning, the National Center for Hydro-Meteorological Forecasting said that the above phenomenon was due to China successfully launching the Thien Chau 9 cargo spacecraft from Van Xuong launch site, Hainan province with a Truong Chinh-7 Y10 rocket.
The launch time is at 5:44 am Beijing time (ie 16:34 am Hanoi time)
Weather expert Huy Nguyen said that the image filmed and taken in the eastern central sky at around 4:40 am is the image of a rocket pushing Truong Chinh 7 (Long March 7) launching the Chinese spacecraft Thien Chau 9 (Tianchou 9) into space.
According to the schedule, the Thien Chau 9 ship will be launched into space at 4:00 p.m. 7:00 a.m. (GMT+7) corresponding to the time period of time we observe in the sky in the East Sea.
The Truong Chinh 7 missile is a hypersonic rocket (speeding 8,575 km/h) that will create a "a sound wall" behind it. The white, hat-shaped air mass behind the hypersonic missile is called condensation cloud orvapor connection. The white spot we see with the naked eye is due to:
Shockwave: When the missile moves at hypersonic speeds, it compresses the air in front to create shock waves. These waves reduce air pressure and temperatures in some areas behind the missile.
Steam condensation: Under low pressure and temperature conditions caused by shock waves, the steam in the air condenses into small drops, forming a white cloud. This cloud is often hat-shaped because shockwaves spread like hats (called Mach hats) from the missile's nose point.
Environmental conditions: This phenomenon is more noticeable in humid air conditions, when there is a lot of water to freeze. If the air is too dry, vents may not appear or are difficult to see.
optical effects: White air mass is not smoke or fuel, but just condensed steam, so it often appears and disappears quickly as the missile moves through airspace with different conditions. The viewer's perspective and the time of observation also show different image quality.
