Tag archives: astronomy
By Brent Tully at the International Astronomical Union General Assembly in Honolulu, Hawaii
We know that we live on a planet in a solar system in a galaxy in a group of galaxies. But what do we know about our location in the universe beyond that? Some astronomers would answer that we live in the “Local” or “Virgo” supercluster of galaxies. However, the concept has been vague. In the interconnected “cosmic web” it has not been clear where one dense region of galaxies ends and another begins.
Rather than just looking at the distribution of galaxies, it is instructive to consider the motions of galaxies with respect to each other. On the grand scale, galaxies are flying apart from each other with the expansion of the universe. We have to cancel out that motion to see the residual “peculiar” velocities of galaxies that arise from local gravitational attractors.
By Andrew Silver
Can the unaided eye see the light from a single candle from 10 miles away? According to some claims on the Internet, the answer is yes – but now two scientists in the US have borrowed techniques from astronomy to show that a pair of binoculars would probably be needed.
The story behind this work began high in the Andes one moonless night when a candle was lit on the Cerro Tololo Inter-American Observatory telescope catwalk. Somebody walked 400–600 m away and said the flame was as bright as the brightest stars in the sky. Nobody wrote down any numbers.
By Hamish Johnston
Earlier this week the triennial XXIX General Assembly of the International Astronomical Union (IAU) kicked off in Honolulu, Hawaii. Founded in 1919, the IUA has about 10,000 members based in 96 countries worldwide. About 3500 astronomers are attending this year’s meeting, which runs until 14 August and is hosted by the American Astronomical Society.
A long-standing tradition of the congress is the production of a daily newspaper for delegates and 2015 is the first year that an electronic version is available to the general public. You can catch up with all the daily news by downloading a copy of Kai‘aleleiaka, which is pronounced “kah EE ah lay-lay-ee AH kah” and means “the Milky Way” in Hawaiian.
By Tushna Commissariat
Mechanics was never my favourite topic when I was studying physics for my BSc, but I think I might have been more interested if we had looked at real-world situations rather than square blocks sliding down an incline plane. A bicycle that carries on, sans rider, without toppling over for quite a long time, for example, would have got my attention. This is a rather well-known quirk of mechanics though and it isn’t even the first time we have discussed it on the blog. Indeed, Physics World‘s James Dacey, a keen cyclist, delved into the topic in 2011. This week, we spotted a a new Minute Physics video on the subject, over at ZapperZ’s Physics and Physicists blog. Watch the video to get a good, if a tiny bit rushed, explanation of the three forces that come into play to allow a bicycle at a certain speed to zip along without its human companion. As the video suggests, all is not known about the secrets of free-wheeling bicycles just yet though, and I have a feeling that we will blog about it again in the years to come.
By Tushna Commissariat
After trundling through our solar system for more than 10 years, NASA’s New Horizons mission made its closest approach to the dwarf planet Pluto earlier today, at 12:49 BST. It was a mere 12,472 km from the planet’s surface – roughly the same distance from New York to Mumbai, India – making it the first-ever space mission to explore a world so far from Earth.
If you want to find out more about the New Horizons mission, read this recent news story by physicsworld.com editor Hamish Johnston. Above is best close-up view of this cold, unexplored world that the spacecraft sent back before its closest approach (when it was still 766,000 km from the surface), revealing in clear detail many of the planet’s surface features, including the “heart” at the bottom.
By Hamish Johnston
Over the past decade or so the Real Madrid football club has acquired a string of high profile players dubbed the “Galácticos”. Now the most expensive of these footballers – the Portuguese forward and Real Madrid number 7 Cristiano Ronaldo – has a distant galaxy named after him. The galaxy is dubbed “CR7” and was discovered by a team of astronomers led by David Sobral of the University of Lisbon using several different telescopes.
CR7 actually has two meanings, the second being “COSMOS Redshift 7”. COSMOS refers to the Cosmological Evolution Survey, which is using a number of telescopes to search for very old galaxies.
By Michael Banks and Tushna Commissariat
You may remember that the “classical crossover” soprano star Sarah Brightman had been undergoing strenuous training at Moscow’s Star City complex before hitching a ride on a Soyuz rocket to the International Space Station (ISS) in September. The singer was set to pay a whopping £30m for a ticket that would have seen her embark on a 10-day journey into space. Brightman even recorded a special song in March that she was planned to perform on the ISS itself – you can watch the 5 News report above. But Brightman has now postponed the trip, putting out a brief statement on her website citing “personal family reasons” for the decision. One beneficiary of Brightman’s no-show will be the Japanese entrepreneur Satoshi Takamatsu, who had been training as Brightman’s back-up. Whether he’ll do his own version of her planned performance isn’t clear.
By Matin Durrani at Sierra Negra, Mexico
Just as my Physics World colleague James Dacey mentioned earlier, neither of us felt super-wonderful yesterday visiting the Large Millimeter Telescope (LMT), which sits at a height of 4600 metres above sea level. Spectacular though the facility is, the air pressure is roughly 60% of that at sea level and there is so little oxygen that even walking up a flight of stairs made me feeling pretty light-headed.
So, James and I were both quite glad to descend with LMT director David H Hughes to a height of 4100 metres, where it was time to visit another leading Mexican astronomy facility – the High-Altitude Water Cherenkov (HAWC) gamma-ray observatory.
By James Dacey at Sierra Negra, Mexico
Friday was the final full day of the Physics World Mexican adventure and we ended with a breathtaking experience, quite literally.
Matin and I rose early in Puebla to travel over a hundred kilometres east to the ominously named Sierra Negra volcano. This extinct beast is home to two of Mexico’s finest astrophysics facilities.
By Michael Banks
The telescope marked the 400th anniversary of Galileo’s first telescope, which he presented to policy-makers from the Venetian Republic on 25 August 1609.