----- Nội dung dịch tự động từ ảnh -----
In 2010, the planetary defense team at NASA had identified and logged 90 per cent of the
asteroids near Earth measuring 1km wide. These 'near-Earth objects', or NEOs, are the size of
mountains and include anything within 50 million kilometers of Earth's orbit. With an estimated 50
left to log, NASA says none of the 887 it knows about are a significant danger to the planet.
Now NASA is working towards logging some of the smaller asteroids, those measuring 140 meters
wide or more. Of the 25,000 estimated asteroids of this size, so far about 8,000 have been logged.
Considering that a 19-metre asteroid that exploded above the city of Chelyabinsk in Russia in 2013
injured 1,200 people, these middle-sized asteroids would be a serious danger.
The planetary defense team would still need to work out how to defend the planet against
being hit by the truly worrying asteroids - the PHAS. Potentially Hazardous Asteroids' are
rocks close enough to pass within 7.5 million kilometers of Earth's orbit, none of which are
expected to be a threat in the next one hundred years. NASA has created a map of 1,400 PHAS.
With technology already available, NASA can track these objects and make predictions about
possible impact, at which point two defense solutions could be launched.
The first is DART - the Double Asteroid Redirection Test. Plans are scheduled to test DART on the
moon of an asteroid called Didymos. 'Didymoon' is 150 meters wide, orbiting its 800-metre mother,
and hopefully the impact of DART will knock it out of its orbit enough for Earth-based telescopes to
pick up.
Another suggested defense against a PHA on course to hit Earth is to blow it up using a nuclear
weapon. It may sound like a plot from a film, but the Hypervelocity Asteroid Mitigation Mission
for Emergency Response (HAMMER) is a genuine NASA proposal. The eight-ton rockets would
be fired at an approaching asteroid with the hope of bumping it off course. If the asteroid was too
close to Earth for this plan to work, the rockets would carry nuclear bombs to blow it up instead.
Question 11 (Question ID: 1-27652)
Which of the following best serves as the title for the passage?
A. Asteroids
B. The PHAS
C. NASA planetary defense team
D. NASA
Question 12 (Question ID: 1-27653)
According to paragraph 1, NEOS
A. are within 7.5 million kilometers of Earth's orbit
B. are all 1km wide
C. are as big as mountains
D. are a significant danger to the planet
Question 13 (Question ID: 1-27654)
The word "logged" in paragraph 1 is closest in meaning to
A. destroyed
B. recorded
Question 15 (Question ID: 1-27656)
It can be inferred from the statement "The planetary defense team would still need to work out
how to defend the planet against being hit by the truly worrying asteroids-the PHAS." that
A. the PHAS will be of no worries at all
B. the PHAs is not expected to be a threat to the earth
C. NASA has already found solutions to defend the planet against being hit the PHAS
D. the PHAs are potentially hazardous to the earth in future
Question 16 (Question ID: 1-27657)
The word "track" in paragraph 3 is closest in meaning to
A. follow
B. find
C. hide
D. knock
Question 17 (Question ID: 1-27658)
As mentioned in the last paragraph, HAMMER is
A. a nuclear weapon
B. a plot from a film
C. a genuine NASA proposal
D. an eight-ton rocket
Question 18 (Question ID: 1-27659)
Which of the following is NOT TRUE according to the passage?
A. Earth does not appear to be in any danger from any asteroids that measure one kilometer wide.
B. We don't need to worry about small asteroids under 20 meters wide.
C. PHAs are the biggest concern, but they're still not an immediate threat.
D. HAMMER may or may not need nuclear weapons to save Earth from an asteroid.
C. defended
D. measured
Question 14 (Question ID: 1-27655)
The word "those" in paragraph 2 refers to
A. the smaller asteroids
B. asteroids measuring 19-metre
C. asteroids measuring 1km
D. asteroids within 7.5 million kilometers of Earth's orbit