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Debora MacKenzie draws attention to the gilets jaunes protests in France as an indicator of the ordinary person's reluctance to pay higher fuel duty prices ( 25 May, p 23 ). The real reason that the rises caused so much furore was president Emmanuel Macron's incompetent and arbitrary imposition of taxes to fight a nebulous …

In your article about the Greenland ice sheet melting, you mention how "bad news begins to wash over you" ( 4 May, p 23 ). I spend time in parts of the US that have a lot of climate change sceptics. Discussing evidence and reasoning is often met with suspicion, or even outright derision, but …

The tech giants' huge revenues are now comparable to those of some nations ( 4 May, p 18 ). But, as Douglas Heaven points out, breaking them up isn't a good solution to their dominance, as new giants will spring up in their place. If tech giants grew without limits, a single corporation could soon …

After reading your article about detecting species fromfree-floating DNA in river and lake ecosystems, it seems to me that the waters of Loch Ness should be tested for unfamiliar DNA, reptilian or otherwise ( 18 May, p 8 ). But I am sure that there are people who would object.

• Asimina Arvanitaki is the first woman to hold a named research chair at the Perimeter Institute ( 1 June, p 46 ). Want to get in touch? Send letters to Â鶹´«Ã½, 25 Bedford Street, London WC2E 9ES or letters@newscientist.com ; see terms at newscientist.com/letters

While I agree with your leader about the political response to global warming, I believe that you are too pessimistic when you say that "dealing with climate change comes with a cost". ( 25 May, p 5 ) On the contrary, making the transition to renewable energy is a natural investment. As the price of …

You report an illusion whereby three matchboxes together appear to be lighter than the heaviest box on its own ( 25 May, p 13 ). I believe this error occurs because we are comparing the weight of the heaviest box not to the total weight of all three, but to the average weight of them. …

I have a couple of observations following your article on the matchbox illusion . First, an item of flat pack furniture seems to be far less heavy once assembled. Second, when the head of a pint of Guinness settles, it appears to have gained weight. Could an object's density fool our perception of its weight?

I commend Debora MacKenzie's article about Iran's nuclear programme, which points out the unintended consequences of US president Donald Trump's withdrawal from the 2015 Joint Comprehensive Plan of Action nuclear agreement ( 18 May, p 11 ). However, I was surprised at the line: "the standard inspections the IAEA does in all countries with nuclear …

Your leader about the new space age made me think back to all the starry-eyed dreams of space travel I had as a child, watching space missions and sci-fi programmes on TV ( 18 May, p 5 ). Where is the vacation on the moon that I was promised? Where is the HAL 9000 from …