Go, also known as Golang, is an open-source programming language created by Google in 2007. It is statically typed, compiled, and known for its simplicity and efficiency. It has a clean syntax, making it easy to learn, and it provides great support for concurrent programming with goroutines and channels.

Here is a simple snippet of Go code from the Docker codebase (specifically, from the Docker CLI main function):

package main

import (
	"os"
	"github.com/docker/cli/cmd/docker"
)

func main() {
	if docker.PreRunCatchall() {
		// If there are no args, then we need to force
		// the help text to be displayed (see #6632)
		os.Exit(docker.RunDocker(os.Args))
	}
}

this code is essentially just a thin wrapper to start running Docker, importing the needed package and running the core function.

Yes, you could hypothetically rewrite Docker in Python or any other language, but the effort would be significant and will require expertise in Python. However, Go offers several advantages which are especially pertinent to the needs of a project like Docker:

1. Performance: Go is generally much faster than Python, as it is a compiled language while Python is interpreted. For a system like Docker that needs to manage system resources, this can be a critical advantage.
2. Concurrency: Go’s support for lightweight ‘goroutines’, which allow for easy management of concurrent tasks, is a standout feature and very useful for a system like Docker which often needs to handle many simultaneous actions.
3. Static Typing and Type Safety: Go is statically-typed, which can lead to preventable errors being caught at compile time, whereas Python’s dynamic typing can increase the chance of runtime errors.
4. Portability: Because Go binaries are statically linked, they can be run on any system without needing to install any dependencies, whereas Python programs require the Python runtime to be installed on the system.
5. Simplicity: Some would argue Go is simpler than Python, especially when compared to Python’s dual-version situation (Python2 or Python3), which can add complexity for systems like Docker that need to be usable in a wide range of deployments.

These reasons make Go an excellent choice for developing scalable, distributed systems, networking tools, data pipelines, and other software infrastructure tools. Some well-known projects written in Go are Docker, Kubernetes, and InfluxDB.

While Python is a great language for many tasks, particularly in data analysis and quick prototyping, it is less commonly used for low-level systems programming like operating system interfaces and resource management, which is where Go shines and why it was chosen for Docker.