Why is there a bridge between these two spiral galaxies? Made of gas and stars, the bridge provides strong evidence that these two immense star systems have passed close to each other and experienced violent tides induced by mutual gravity.
Known together as Arp 240 but individually as NGC 5257 and NGC 5258, computer modelling and the ages of star clusters indicate that the two galaxies completed a first passage near each other only about 250 million years ago. Gravitational tides not only pulled away matter, they compress gas and so caused star formation in both galaxies and the unusual bridge.
Galactic mergers are thought to be common, with Arp 240 representing a snapshot of a brief stage in this inevitable process. The Arp 240 pair are about 300 million light-years distant and can be seen with a small telescope toward the constellation of Virgo. Repeated close passages should ultimately result in a merger and with the emergence of a single combined galaxy.
Image Credit: NASA, ESA, Hubble Space Telescope; Processing & Copyright: Chris Kotsiopoulos
Source: APOD NASA
How could that city be upside-down? The city, Chicago, was actually perfectly right-side up.
The long shadows it projected onto nearby Lake Michigan near sunset, however, when seen in reflection, made the buildings appear inverted.
This fascinating, puzzling, yet beautiful image was captured by a photographer in 2014 on an airplane on approach to Chicago’s O’Hare International Airport. The Sun can be seen both above and below the cloud deck, with the later reflected in the calm lake.
As a bonus, if you look really closely — and this is quite a challenge — you can find another airplane in the image, likely also on approach to the same airport.
Image Credit & Copyright: Mark Hersch
When it comes to spectacular scenery, few people get a better view than airline pilots. But instead of keeping those beautiful panoramas to himself, 747 pilot Christiaan van Heijst take stunning photographs that he kindly shares with the rest of us stuck in economy.
“From an early age on I have found great joy in capturing the beauty of natural light in all its forms,” writes Heijst on his website. “Later on, I combined that with flying and a new passion emerged. Seeing the entire world in my job, I feel privileged to be in a position to capture many different parts of the planet through my camera and immortalize the beauty of the places I visit.” Shooting with a Nikon D800, the flying Dutchman captures beautiful pictures of thunderstorms, sunsets, full moons, and even the northern lights.
More info: Christiaan van Heijst
In this interesting (and slightly terrifying) photo we see a huge hornet nest atop a statue that has a striking resemblance to a turban. You can also see a large number of hornets covering other parts of the statue so be sure to observe this nest from afar.
The photo was submitted earlier this month to reddit where it reached the front page and the top of /r/mildlyinteresting
via twistedsifter navy966 on reddit
Randall Munroe of XKCD put together this fascinating chart of the “ionizing radiation dose a person can absorb from various sources;” from using a cell phone to CT Scans to being at Chernobyl and Fukushima when disaster struck.
Munroe received help from Ellen, a Senior Reactor Operator at the Reed Research Reactor, and you can find a list of the sources used here.
As far as accuracy, Munroe also adds:
“It’s for education purposed only. If you’re basing radiation safety procedures on an internet PNG image and things go wrong, you have no one to blame but yourself.”
What do we really know about the range of temperatures in the universe? Probably not much. We perceive the world based on our ’earthly’ feelings: we are cold when the temperature drops below −20°C, and we sweat when it gets higher that 35°C.
To help you get a better idea of what hot and cold really mean, BBC Future teamed up with the Information is Beautiful Studio have created an interesting infographic.
Let’s explore the temperatures of the Universe from Absolute zero (–273.15°C or –459.67°F) to ‘Absolute hot‘ or Planck temperature, which has the value 1.416785(71)×10^32 kelvin (where 1 kelvin = [°C] + 273.15 or ([°F] + 459.67) × 5⁄9); below which, conventional laws of physics break down.