How can astronomers know things for certain since they only look at space from one vantage point?

How can astronomers know things for certain since they only look at space from one vantage point?

How Astronomers Revolutionized Our View of the Cosmos

What other planets can teach us about Earth

How do astronomers know what distant space looks like even when they can't view it or send instruments to those areas? - Quora

7 Mysteries of Space That Scientists Can't Explain

Universe - Wikipedia

Why the Search for Life in Space Starts With Ancient Earth

How Do Galaxies Get Into Formation?

Starry, starry night: Grasping just how vast the universe really is

The Promise of Astronomy on the Moon, Air & Space Magazine

Astronomers Chase a Very Eccentric Interstellar Object - The Atlantic

Scientists: We're 'very close' to finding another Earth

Sending a tiny telescope past Saturn may solve mysteries of the universe

Astronomers look back 11 billion years and find oldest galaxy ever seen

Herschel Reveals Details of Distant Galaxies & Quasars - SpaceRef