How big can the floating objects be on the space?

Let's get the answer by starting with a journey from the moon: a
celestial body which can be regarded as fairly big:
The Moon...
Mercury...
Mars...
Venus...
Earth... We live here
Neptune
Saturn
Jupiter
The Sun... Our star
Sirius A
Pollux… An Orange Giant
Archturus... A Red Giant
Aldebaran… A Red Giant
Ragil… A Blue Super Giant
Pistol Star… A Blue Hyper Giant
Antares A… A Red Super Giant
Mu Cephei… A Red Supergiant
VY Canis Majoris... A Red HyperGiant: known as the biggest star
The Size Of the Earth is 12,756 km.
This star is 1,975,000,000 km in diameter.
How can you imagine this size on your mind?
Imagine an airliner which goes with 900 km per hour and flying
around this star.
Just one circuit of an airliner around this star would last exactly
1,100 years.
The size of the star on a picture which shows our galaxy is only as
big as a spot on a piece of paper.
And our galaxy ... would be seen only as big as a spot in the
vastness of the universe.
"Assuredly the creation of the heavens and the earth is a greater
(matter) than the creation of men: Yet most men understand not."
(Surah Al-Ghafir, 57)