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2T2B4HK One man walking by a close up of a pair of eyes from a portrait painted by Antonello de Messina on a poster in central London

Could two three-dimensional images create a four-dimensional one?

Yes, says one reader, who goes on to speculate about what else might be possible

2DAC6P0 Sculpture 'Medics to the World' honouring the health care workers battling Covid-19

There are good and bad bacteria, but are there good viruses? Part 2

The events surrounding the Big Bang were so cataclysmic that they left an indelible imprint on the fabric of the cosmos. We can detect these scars today by observing the oldest light in the Universe. As it was created nearly 14 billion years ago, this light ???????? which exists now as weak microwave radiation and is thus named the cosmic microwave background (CMB) ???????? has now expanded to permeate the entire cosmos, filling it with detectable photons. The CMB can be used to probe the cosmos via something known as the Sunyaev-Zel????????dovich (SZ) effect, which was first observed over 30 years ago. We detect the CMB here on Earth when its constituent microwave photons travel to us through space. On their journey to us, they can pass through galaxy clusters that contain high-energy electrons. These electrons give the photons a tiny boost of energy. Detecting these boosted photons through our telescopes is challenging but important ???????? they can help astronomers to understand some of the fundamental properties of the Universe, such as the location and distribution of dense galaxy clusters. The NASA/ESA Hubble Space Telescope observed one of most massive known galaxy clusters, RX J1347.5????????1145, seen in this Picture of the Week, as part of the Cluster Lensing And Supernova survey with Hubble (CLASH). This observation of the cluster, 5 billion light-years from Earth, helped the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to study the cosmic microwave background using the thermal Sunyaev-Zel????????dovich effect. The observations made with ALMA are visible as the blue-purple hues. Links ESO Picture of the Week RX J1347.5????????1145 seen by Hubble only

This week’s new questions

Last Word

What is a smooth continuous curve with three axes of symmetry called?

Krakow, Poland - 4 May 2024: Large old antique medieval book written in Latin gothic font, colorful illuminations object closeup museum exhibit, Dominican monastery Old religious books concept; Shutterstock ID 2516551261; purchase_order: -; job: -; client: -; other: -

How and why did complex languages like Latin develop? Part 2

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This week’s new questions

Spaceman walks on the red planet Mars. Space Mission. Astronaut travel in space; Shutterstock ID 532139260; purchase_order: -; job: -; client: -; other: -

Should we be thinking about genetic modifications for humans on Mars?

H3NTB2 Woman by giant trees in snow-covered forest, Sequoia National Park, California, USA

Why don’t trees rot in the ground, while wooden structures do?

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This week’s new questions

2DAC6P0 Sculpture 'Medics to the World' honouring the health care workers battling Covid-19

Are there good viruses? What would happen if all viruses disappeared?

There certainly are good viruses, say our readers - who also paint a gloomy picture of what would happen if all viruses disappeared

Why do our nostrils point down, not straight out from our faces?

This week’s new questions

How and why did grammatically complex languages such as Latin develop?

Why did some species survive the Cretaceous-Palaeogene extinction?