What Einstein’s theory means for a cyclist moving at almost light speed

Advice from special relativity: avert your eyes as that bicycle whizzes by. Advice from special relativity: avert your eyes as that bicycle whizzes by.

Physicists have made the most realistic calculations yet of what a cyclist would look like if moving at close to the speed of light -the scenario in a classic thought experiment of special relativity.
Albert Einstein's special theory of relativity implies that the dimensions of a fastmoving object are squashed along the direction of motion. But the implications for how the object looks to an observer are subtle. Different parts of the cyclist are at slightly different distances from the observer, so a photograph of the rider would be made up of photons that left the cyclist and bicycle at different times. As a consequence, the cyclist would look grotesquely distorted, with their back visible even when they were approaching.
Evan Cryer-Jenkins and Paul Stevenson at the University of Surrey in Guildford, UK, have calculated the 3D view seen not by a single camera but with binocular vision. Because the two eyes see different distortions, the authors speculate that a human observer would get motion sickness.
The research could help astronomers to design sensors for future interstellar probes moving at extremely high speed. Proc. R. Soc. A 476, 20190703 (2020)

TRACE EVIDENCE: DNA BARCODES MAP PRODUCTS' PATHS
A method that uses harmless microorganisms as biological labels could allow consumers to find out which farm grew the salad that made them sick and whether the designer shoes they bought were counterfeited.
Michael Springer at Harvard Medical School in Boston, Massachusetts, and his colleagues inserted short DNA sequences into the genomes of inactive forms of the bacterium Bacillus subtilis and the yeast Saccharomyces cerevisiae. The DNA sequences serve as biological barcodes that can be used in different combinations and identified with several DNAdetection tools.
Barcoded microbes that were sprayed onto sand, soil, carpet and wood remained detectable for months, even after being exposed to wind, rain, vacuuming or sweeping. They could also be transferred from surfaces to other objects, such as shoes worn in a sandpit that had been sprayed with the microorganisms.
Using DNA-tagged bacteria, the researchers were able to map a leafy plant back to the specific pot in which it was grown. The barcoded microbes persisted on produce even after washing and cooking, so the approach could be used to track food contamination to its source, the researchers say.

TEST DETECTS FAINTEST HINT OF TUMOUR'S PRESENCE
A genomic technique that detects minuscule quantities of tumour DNA in the blood could help to determine whether people who have had tumourremoval surgery are cancer-free or need further treatment.
Available tests do detect DNA that tumours (pictured) shed into the bloodstream, but can miss low levels of cancer DNA in people whose tumours have largely been surgically removed.
Dan Landau at the New York Genome Center in New York City and his colleagues sequenced the genomes of tumour and normal cells from people with cancer, to create a 'mutational fingerprint' -a list of the mutations in each person's tumour. The team trained an algorithm to compare a fingerprint with DNA from a blood sample. The algorithm identified tumour DNA even when it comprised only 0.001% of the DNA in the bloodstream.
The team tested this approach on people with colon or lung cancer whose tumours had been removed. Individuals positive for circulating tumour DNA after surgery tended to have a high risk of relapse, whereas none of those with a negative test showed cancer recurrence in the study follow-up period. Nature Med. http://doi.org/dxqd (2020)

MOBILE PHONES DIAL UP EQUALITY FOR WOMEN
Possession of a mobile phone has been linked to greater gender equality and improved maternal health, especially in lower-income nations.
Valentina Rotondi at the University of Oxford, UK, and her colleagues compared the prevalence of mobile-phone subscriptions in 209 countries with data on women's health and freedoms from 1993 to 2017. The team found that countries with more mobile phones per capita have less gender inequality and lower maternal and child mortality. These correlations hold even when controlling for gross domestic product and other developmental indicators.
Surveys of girls and women aged 15 to 49 in 7 sub-Saharan African countries support the correlation. Women with mobiles were more likely to have decision-making power in their households and to use contraception than were women without them. The poorer the country, the greater the effect of mobile ownership.
It's possible that women are simply more likely to own mobile phones in places where they are more empowered than in places where oppression is greater. The team calls for further studies, but says that, in the meantime, getting phones into women's hands should be a priority.