Down from ceiling

It helps form both - though the cave comes first!

The CO2 solutuion is slightly acid - carbonic acid - and this dissolves the calcium carbonate that is limestone's main constituent.

they are sedimentary

Stalactites a rock that hangs in the cave is formed by slow drips of water, when joined with stalagmites the rock below that grows upward will become a column. Column in a cave is formed when stalactites and stalagmites finally joined together. Over the years, it is possible to become wider.

However, if you are asking the rocks that will form as stalactites and stalagmites, this include limestone, dolomite, and gypsum to mention a few.

A "stalagmite" is a calcareous accretion that grows up from a cave floor.

A "satellite" is a natural or man made object that orbits the Earth.

a column

what does it mean when someone says stalactites stem from the ceiling of a cave

In theory you could in a laboratory if you establish conditions conducive to rapid precipitation and crystallising of the calcite - but I don't know why you would need to when it's easier to analyse natural ones!

in france the buggest staligmite on record is found .

I believe what you're referring to is actually a 'Stalagmite.' A stalagmite is the build-up of drippings from the ceiling of a cave rich in limestone and other minerals.

Over thousands of years the continual drip, drip, drip, begins to solidify, appearing at first as little more than a smooth spot on the cave floor. In time, as the same drip perpetually hits the same spot below, the minerals accumulate and eventually begin to rise from the bottom of the floor. After thousands and even millions of years, those cumulative drips create a spherical cone which reaches towards the ceiling of the cave.

In the same theme, it is most probable that the same period of dripping from the ceiling, begins to create a downward-facing cone, which often looks like an icicle. Consequently, the downward cone grows almost at the same rate as the upward growing cone. These hanging cones are referred to as 'Stalactites.'

Over time, the two will eventually meet. When this occurs and the Stalactite has now formed with the stalagmite, this is referred to as a column.

Not all Stalactites and stalagmites are cylindrical. They can overlap, similar to a soft ice-cream cone and some even contain smaller stalactites and stalagmites within the original column. Some become truly stunning creations of natural beauty.

Should you discover one in a natural setting, you should never touch them as it can destroy the centuries of time required for the process to begin. Placing your hand on the point of drip effectively 'kills' the growth process.

It is very variable, depending on many interacting factors.

A common rate often quoted by show-cave guides is "an inch in a thousand years", and while that might be the mean value for that cave, it is by no means universal.

Further, the rate can vary with time and climate change, to the extent that analysis of speleothems' growth rates is now used as one of various tools in palaeoclimate studies.

No. They are precipitations of calcite. Draughts may influence their shapes, and are thought one way in which helictites develop.

They are carbonate deposits formed by dripping

water in air-filled cavities.