Objects with mass have a gravitational attraction between them. A basketball has a gravitational interaction with Earth (since they both have mass).

So, astronomers can measure one or both of these quantities to derive the mass of a galaxy’s central supermassive black hole.

The mass of an object tells you how heavy something is. You can measure mass in grams (g) and kilograms (kg). Light items, like apples and bananas, are measured in grams. Heavy objects, like a toy ...

Your iPhone or iPad can use the free Measure app to take basic measurements. If you have a newer device, you may have more complex measuring options.

How Einstein helped measure a dead star General relativity suggests that objects of great mass "warp" the very fabric of space-time. The greater the mass, the larger the "dent" in space it causes.

Researchers measure the gravity exerted by a 90 milligram object We've measured the pull between two gold spheres, each 2 millimeters across.