Read this excerpt from "Why Are They Called Black Holes?" Scientists cannot see gravity, but they can see its effects. The gravity of a black hole will swallow matter and light that drift close enough to it. Some light passing by a black hole can be far enough away that it could avoid being sucked in, but the path of the light would still be bent by gravity.

Astronomers can observe these effects. For example, when a black hole passes through a cloud of dust, it pulls the dust inside it like a big gravity-powered vacuum cleaner. When a star passes too close to a black hole, the black hole pulls it in and breaks up the star, spewing giant flashes of high energy called gamma-ray bursts. And when scientists see light bending even though there is no visible matter nearby, they have evidence that there is an invisible black hole.

What must be present for scientists to detect black holes?

a cloud of dust
a gamma ray burst
the loss of a star
the force of gravity

i think the answer is hope it

wordsworth tends to see nature as 'out there'; a presence which surrounds humans, and contributes to human life, but is different from humans. if you look at a typical wordsworth poem (there was a boy, ye knew him well ye rocks) - wordsworth talks about nature as something that needs to be learned about and understood, nature is different from us.  

if you look at a byron poem (the isles of greece is a good one) - byron looks at nature mainly for what it already means to man. wordsworth will look at a landscape and see the mountains, trees, valleys, and rivers as almost spiritual presences - wordsworth wants to get to know nature.  

byron will look at the same landscape and he will want to know who lives there, what are the villages? are there any farms or mines, is there some history?  

wordsworth looks at nature for what it is; byron is forever asking what it means.  

wordsworth thinks that humans are part of nature; byron thinks that nature is part of being human