Read the excerpt from A Black Hole Is NOT a Hole by Carolyn Cinami DeCristofano.


Most of the time gravity seems to work the way Newton described it. Newton's rules explain a lot, from falling apples to most planets' orbits. But his laws don't work perfectly. In high-gravity zones, Newton's ideas don't jibe with what scientists observe. For example, Mercury's orbit—up close to the Sun—has a blip in it that Newton's laws can't explain.


Glitches like this one were the reason Einstein worked so hard at coming up with a new explanation. He wanted to account for everything. His ideas about curving space may sound bizarre, but they work! They took care of the gaps in Newton's theory and explained Mercury's orbit. They led scientists to predict shifting starlight and black holes. All of this is powerful evidence that Einstein was on to something.


In which order would events appear on a timeline based on the details in the excerpt?


1. Newton developed his laws of gravity.

2. Scientists predicted black holes.

3. Einstein developed his explanation of gravity.

1. Scientists predicted black holes.

2. Newton developed his laws of gravity.

3. Einstein developed his explanation of gravity.

1. Newton developed his laws of gravity.

2. Einstein developed his explanation of gravity.

3. Scientists predicted black holes.

1. Einstein developed his explanation of gravity.

2. Newton developed his laws of gravity.

3. Scientists predicted black holes.