Read a scientific article about asteroids to practise and improve your reading skills.


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Reading text


In 2010, the planetary defence 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 kilometres 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 metres wide or more. Of the 25,000 estimated asteroids of this size, so far about 8,000 have been logged, leaving 17,000 unaccounted for. 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 if they enter Earth's orbit.


Whether NASA can find the remaining middle-sized NEOs depends on getting the money to build NEOCam, a 0.5-metre space telescope which would use infrared light to locate asteroids. If it did get the money, it could probably achieve its goal in ten years. Once logged, the planetary defence 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 kilometres of Earth's orbit. NASA has created a map of 1,400 PHAs, none of which are expected to be a threat in the next one hundred years. With technology already available, NASA can track these objects and make predictions about possible impact, at which point two defence 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 metres 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 defence 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, and it was the subject of the 1998 film Armageddon, 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.


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Submitted by mxoubi0 on Wed, 26/08/2020 - 10:47

Hi Teacher, I think the writer should use will instead of using would since this is a first conditional statement. Please correct me if I am wrong. "these middle-sized asteroids would be a serious danger if they enter Earth's orbit"

Hello mxoubi0,

You could certainly say 'will' here, and if you saw a sentence like this on a grammar test, that would be the best choice since, as you point out, it follows the rules that are taught about the first conditional.

These rules about conditionals explain how grammar is used most of the time, but they are rules designed by teachers to help students. In reality, you can find sentences like this one, which is perfectly correct. Here, I imagine that the writer chose to say 'enter' since the previous sentence mentions a specific middle-sized asteroid that did indeed enter Earth's orbit. But the danger such an asteroid would pose is still regarded as hypothetical, which is more in line with what the writer's tone in the rest of the text.

I can see how that may be a little confusing, but I hope this helps you make sense of it.

Best wishes,


The LearnEnglish Team

Submitted by Truicab on Fri, 17/07/2020 - 10:16

Wow, it's a difficult question.. I think that with everybody crying in state of panic, I couldn't do many things. Try to stay with my family believing in the salvation jjjjj

Submitted by Aakash Jain on Fri, 12/06/2020 - 03:07

Firstly, I will confirm whether the information is true or not through ISRO/NASA latest updates and if it is correct, then I'll check regarding the extent of damage it may cause. If it is going to be too serious , then I will first apologize to everyone if I had done anything wrong to them and secondly remain with my family till the problem is not over. It's better if we all remain together during such times.

Submitted by Muhammad Bagir on Sat, 23/05/2020 - 04:51

I think I will rewatch the movie about space, and try to applying it in my situation. This is a huge problem, so it need a huge solution too

Submitted by Ahmadbassam on Fri, 22/05/2020 - 20:55

Firstly, I would make sure if this news true or fake. Secondly, i would inform my family about it. Then, i would follow the authorities. Finally, i would pray.

Submitted by jsanchezv on Sat, 16/05/2020 - 22:12

It is a complicated question, since if I heard that an asteroid is close to the earth, If would be advisable to report to NASA, but, obviously they would know about this information because they have all the technical equipment for know in any moment when a type of asteroid is going in the way of the earth. If the asteroid is so big and this is will be produce a considerable impact in the surface of this planet, I would go to my home to give a very big hug to my family, to said that independently of what will happen I love all of them. :)
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Submitted by OlaIELTS on Tue, 05/05/2020 - 13:13

I would notify NASA about it.

Submitted by Daudau0601 on Sat, 25/04/2020 - 04:45

It's so excited question. If i heard that an asteroid near the Earth, first of all i would try to check these news were right from NASA or fake because nowadays there are many fake news posted to get evil purpose. If these news were right, it would be hazardous for our planet. May be the asteroid will destroy total it and life no longer exists. But personally i think NASA will find anyway to solve these problem and save our planet because of its their mission.