Synthetic human embryos let researchers study early development while sidestepping ethical and logistical hurdles 
Orbital resonance − the striking gravitational dance done by planets with aligning orbits 
Archeoastronomy uses the rare times and places of previous total solar eclipses to help us measure history 
Larger and more frequent solar storms will make for potential disruptions and spectacular auroras on Earth 
Alpha, beta, theta: what are brain states and brain waves? And can we control them? 
How do airplanes fly? An aerospace engineer explains the physics of flight 
If life exists on Jupiter’s moon Europa, scientists might soon be able to detect it 
Customizing mRNA is easy, and that's what makes it the next frontier for personalized medicine − a molecular biologist explains 
Black hole, neutron star or something new? We discovered an object that defies explanation 
The mystery of consciousness shows there may be a limit to what science alone can achieve 
Our survey of the sky is uncovering the secrets of how planets are born 
The rising flood of space junk is a risk to us on Earth – and governments are on the hook 
The brightest object in the universe is a black hole that eats a star a day 
Eggs from men, sperm from women: how stem cell science may change how we reproduce 
Six space missions to look forward to in 2024 
Why now is the time to address humanity’s impact on the moon 
Pigeons consider safety and food availability in picking where to perch, according to Keio University professor emeritus of animal behavior, Shigeru Watanabe.
The finding could help cities manage pigeon population.
With many natural enemies, pigeons huddle together to reduce the danger of falling prey to a predator.
Another key consideration is whether food is available.
This explains why 30 or so pigeons perch on a car rooftop parked in central Tokyo in November, rather than an adjacent small park.
According to Watanabe, pigeons have figured out that they risk being attacked by crows if they perch on a utility cable. And if they rest on the ground, they automatically become the target of cats.
He added that pigeons are aware that they will be less likely to be attacked if humans are around.
According to Watanabe, the birds also have a flock mentality in that they follow whatever their leader does.
In this particular park, some people ignore the rule that feeding pigeons are prohibited.
Watanabe analyzed that the pigeons may be waiting for people to feed them while they perched in a place where the risk of being attacked is low.
He added that the pigeons are able to recognize individual human faces.
