Keyword Analysis & Research: why is it called the event horizon

Keyword Analysis

Keyword	CPC	PCC	Volume	Score	Length of keyword
why is it called the event horizon	1.61	0.6	6003	57	34
why	1.46	0.6	9030	43	3
is	1.29	0.1	7539	48	2
it	0.57	0.1	4392	85	2
called	1.23	0.8	3031	79	6
the	1.47	0.9	3455	90	3
event	1.13	0.9	4218	91	5
horizon	1.08	0.1	9511	85	7

Keyword	CPC	PCC	Volume	Score
why is it called the event horizon	0.15	0.1	1995	16