# How loud is the boom when a ship appears in the space?

Before I begin, excuse me if any words or terminology is not used correctly.

Now said that, in the latest entry in the franchise Star Wars, The Last Jedi, we are shown in the starting itself that a group of people are on a planet preparing themselves. And all of a sudden a loud boom sound is heard to one of the people, who gets surprised and exclaims her fear.

In the next scene, we are shown a cloud trail in the sky. After that in the space we are shown a ship appearing suddenly, in a boom, followed by other ships.

So my question is - how loud is the boom sound when a ship appears? Has there been any mention of this in the series (irrespective of platform)? Because the people on the planet were able to hear it properly.

• In Star Wars, everything that happens in space is audible, and the speed of sound in a vacuum is of course exactly the same as the speed of light....
– user43022
Dec 18, 2017 at 14:42

## We don't know...probably

The only comparison we have is to a Sonic Boom on Earth

A sonic boom is the audible component of a shock wave in air. The term is commonly used to refer to the air shocks caused by the supersonic flight of military aircraft or passenger transports such as Concorde (Mach 2.2, no longer flying) and the Space Shuttle (Mach 27). Sonic booms generate enormous amounts of sound energy, sounding much like an explosion; typically the shock front may approach 100 megawatts per square meter, and may exceed 200 decibels.

...

The sound of a sonic boom depends largely on the distance between the observer and the aircraft producing the sonic boom. A sonic boom is usually heard as a deep double "boom" as the aircraft is usually some distance away. However, as those who have witnessed landings of space shuttles have heard, when the aircraft is nearby the sonic boom is a sharper "bang" or "crack". The sound is much like the "aerial bombs" used at firework displays.

The width of the boom “carpet” beneath the aircraft is about one mile for each 1000 feet of altitude. For example, an aircraft flying supersonic at 50,000 feet can produce a sonic boom cone about 50 miles wide. However, parts of the sonic boom carpet are typically weaker than others.

NASA

## But...

...this is not happening on Earth so the atmospheric make-up might be different so any definitive answer is impossible.

• hmm, valid point. So i believe there isn't any reference of this in the franchise also (Movie or TV). Dec 15, 2017 at 20:39
• Plus, when ships arrive low over a planet, they're apparently using repulsors (antigravity) to hold them aloft in relative position to locations over planet, rather than being in orbit, so it's entirely plausible they're arriving in the atmosphere. Dec 17, 2017 at 21:16