Question

17,000 miles per hour. this makes tracking orbital debris critical to future space flight. in 2010, nasa and the u.s. military launched a space - based space surveillance (sbss) system to monitor more than 500,000 objects currently orbiting earth. the objects range in size from as small as a marble above earth, augmenting existing telescope and radar systems that track space junk from the ground. unlike ground systems, however, this satellite doesnt encounter weather problems like electrical storms or sunspots that might limit its capabilities. engineers use this data to design flight paths in orbits that are free from debris. they also anticipate collisions and strategically move spacecraft out of the way. sometimes these evasive techniques arent possible or even practical, as in the space stations near - miss with a satellite fragment. even when they do succeed, this avoidance isnt decreasing the existing volume of space junk. scientists are now searching for ways to relocate objects to eliminate them completely. a current nasa experiment involves focusing a laser on pieces of space junk to prod them away from spacecraft or cause them to deorbit. the laser might also be used to completely obliterate debris. hitting a tiny fragment at a distance of more than 400 miles, however, requires extreme laser precision. the defense advanced research projects agency (darpa) has other cleanup ideas. its study, dubbed operation catchers mitt, proposes using a massive net carried by a satellite to pull space trash together, like in a giant garbage bag. the space mitt would use an umbrella to corral tiny bits of waste as well as employ magnets to help close the mitt. debris caught in the mitt would be pulled toward earth and would burn up as it enters earths atmosphere. thats an enormous task as the space mitt would need to catch about 20,000 objects larger than a softball to successfully clear out all of the current junk in space. which sentence best describes the authors opinion of scientists ideas about relocating or eliminating space junk, as described in paragraph 8? 1. their ideas are far - fetched and will gain very little support. 2. their ideas are interesting but may be difficult to carry out. 3. their ideas are excellent and should be put into action immediately. 4. their ideas are promising but putting them into practice will be very costly.

Explanation:

The text in paragraph 8 mentions that scientists are searching for ways to relocate or eliminate space - junk, but current NASA experiments involving focusing a laser on space junk to push it away or using magnets to pull space trash together are not yet fully practical. It implies that while the ideas are interesting, implementing them may face difficulties.

Answer:

1. Their ideas are interesting but may be difficult to carry out.