The evasive identity of the serial killer in 19th century England is still unknown to us. Many speculated at the time that the one responsible for the brutal murders was a man. Everybody was looking for Jack the Ripper. But there were a few who had thought otherwise. Instead of a Jack, they had surmised that the culprit was a Jill.

The “Jill the Ripper” theory has a surprisingly legitimate origin story. Right after the murder of Mary Kelly — the victim with the missing heart — people started arguing about the time of her death.

The police surgeon said that she died in the wee small hours of the morning, but a woman named Caroline Maxwell swore up and down that that was impossible, because she’d seen Mary Kelly a good five hours after she was supposed to have been chopped up into little pieces. Caroline had recognized Mary’s outfit, and even spoken to her.

This weird little discrepancy caught the ear of Frederick George Abberline, a Chief Inspector for the London Metropolitan Police, who remembered seeing burnt women’s clothing in the fireplace of Mary Kelly’s room.

What if the killer had burned their own blood-soaked clothes and changed into Mary’s clean clothes as a means of disguise? What if Caroline Maxwell had unwittingly talked to the actual murderer that morning, dressed up as the victim?

And if so — if the clothes in the fireplace were women’s clothes, and Caroline Maxwell had spoken to someone with a women’s voice — well, Abberline suggested, perhaps they were dealing with a murderess.

(Image credit: Wikimedia Commons)

Looking for fossils is painstaking work. Sometimes you have to dig deep underground. Other times, you have to trek cliffs and chisel your way through just to get to those dried bones. Those toils were nothing to Mary Anning, whose passion for paleontology made her an expert of the Jurassic Period.

Anning inherited her interest in bone collecting from her father. Also a fossil collector, he unearthed the “curiosities,” which he then polished and sold to the tourists visiting the area.

He died young, and Mary, along with her mother and brother, had to continue their fossil business to survive. For Anning, however, fossil hunting was more than a way to make ends meet. Over time, she became an expert in describing and classifying fossils.

(Image credit: Henry De la Beche/Wikimedia Commons)

Opportunity has been quite abuzz in the space exploration community when it was finally retired after 15 years exploring Mars, much longer than its expected useful life of 90-sol.

With all the data it gathered, Opportunity has paved the way for future missions that could go in for the long haul much like it did. Though it isn't the only mission that lasted for a long stretch, NASA could use what they have learned for their next expeditions in space.

To make sure that interstellar probes, planetary explorers, and even the ground-based system that support them do not fail, or at least maximize the time until failure, NASA has developed a massive body of very specific and very stringent workmanship standards.

As Gerrit Coetzee pointed out a few years back, the workmanship standards documents are themselves works of great beauty. They cover every conceivable kind of electromechanical assembly, showing the “NASA way” of doing it correctly.

How to solder correctly, when to crimp instead, how to prevent PCB damage, how to prevent electrostatic discharge damage, and even how to properly tension wire ties are all covered. For my money, though, the pièce de résistance is the section on lacing wiring harnesses. Pure engineering beauty.

(Image credit: Hackaday)

Babies can recognize the voice of their parents and respond to them. Now, a new study suggests that infants can also distinguish between social relationships through vocal cues.

Infants as young as five months can differentiate laughter between friends and that between strangers, finds a new study by researchers at New York University and UCLA. The results suggest that the ability to detect the nature of social relationships is instilled early in human infancy, possibly the result of a detection system that uses vocal cues.

(Image credit: Thiago Cerqueira/Unsplash)

Sloths are some of the most adorable creatures. With their gentle, docile demeanor, they just plod along without much care in the world. Though we see most sloths on land, ancient giant sloths have been found to be great swimmers.

Eli Amson, a paleontologist at the Museum für Naturkunde in Berlin, Germany, is one of the researchers who undertook this osteological revision. After reexamining the fossils, Amson and his team found that Thalassocnus was more at home in the water than previously thought. Some of the changes seen through a succession of five distinct Thalassocnus species are similar to those observed in cetaceans as they evolved to life in the sea.

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Three years ago, a pair of astronomers hypothesized the existence of Planet Nine but have still yet to verify its existence. They were Konstantin Batygin and Mike Brown. Given the presence of several dwarf planets on the outer skirts of our solar system, they concluded that there must be a planet messing with their orbits.

In recent years, a number of small worlds in the outer solar system such as Eris, Sedna, and Makemake have joined Pluto in dwarf planet category. Enough of these small, distant worlds have been discovered that astronomers started noticing a pattern: Many of them have extremely elongated orbits. Sedna, for instance, gets about 7 billion miles from the Sun at its closest, and almost 90 billion miles at its farthest. Sedna isn’t alone; nearly every significant object we’ve found past Pluto has an orbit that looks like a flat oval.

This is particularly weird because extremely ovular orbits don’t just happen on their own. This type of orbit can only be formed in a few ways: either all of these worlds were rogue planets captured by our Sun, or their gravity was disrupted by something lurking in our outer solar system.

It hasn't been confirmed whether this occurrence was caused by Planet Nine but it is one possibility that astronomers are considering. Both Batygin and Brown have been gathering data and evidence to support their hypothesis but no actual sighting of Planet Nine has been made.

(Image credit: R. Hurt/Caltech)

We simply can't get enough of Richard Feynman. He was a pretty cool guy who knew a lot of complicated things and made it easier for others to understand them. He was quite a curious fellow and loved learning about different things. He also loved life and to see the beauty of it.

What made him most endearing to people, however, was his personality. In fact, he was a very cheeky individual.

He was famous for pulling many pranks when he was at Los Alamos.

He was in love with verbal swordplay and jokes. That made him a fascinating figure at every party although it did get him into trouble with friends, family, and colleagues many times.

Most of his memories of Los Alamos talk more about his pranks on people and less about his studies there. He is one of those unique physicists who enjoyed playing pranks.

(Image credit: Wikimedia Commons)

About 11 seconds before we make our decision, neuroscientists can basically predict our decision by reading our brain activity. Not exactly mind reading since this has more scientific grounds, but it's pretty cool nonetheless.

In the study, 14 participants—each placed in an fMRI machine—were shown two patterns, one of red horizontal stripes and one of green vertical stripes. They were given a maximum of 20 seconds to choose between them.

Once they’d made a decision, they pressed a button and had 10 seconds to visualize the pattern as hard as they could. Finally, they were asked “what did you imagine?” and “how vivid was it?” They answered these questions by pressing buttons.

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A few days ago, NASA's solar dynamics observatory gave us a very weird phenomenon: the moon, after passing the sun, seems to have retraced its orbit and went on the reverse. But apparently this is nothing new.

The Moon's unusual apparent behavior during this particular transit is a phenomenon similar to retrograde motion: When a celestial object appears to move backwards because of the way that different objects move at different speeds at different points in their orbits.

(Image credit: NASA/Goddard/SDO)

April 6th. That's the date when this Y2K bug will take effect. It only affects older GPS devices so as long as yours has an updated software, it will be unaffected. However, for those affected, the consequences are quite serious.

The rollover issue itself is caused by the fact that GPS systems count weeks using a ten-bit parameter. This means they start counting at week zero and reset when they hit week 1,024. The first count (or “GPS epoch”) started on January 6th, 1980, and the first reset took place on August 21st, 1999. That means the next one is due April 6th this year.

Check your GPS devices and update them while there's still time.

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Astronomical clocks have been around for centuries and people have been studying the stars and the planets for way longer than that.

So it isn't a surprise to see astronomical devices that, apart from telling time, gather information like the position of the Sun and Moon relative to the Earth at a certain point of the year. The Prague Astronomical Clock is one of the oldest functional ones to date. Here are some information behind how it was built and how it works.

(Image credit: Wikimedia Commons)

Floating about somewhere in the Antarctic are icebergs with a curious shade of green. Apart from looking pretty in a photo, these green icebergs may actually serve a crucial role in maintaining the ecosystem of the oceans.

Scientists have had their pet theories about green ice, but the study from glaciologist Stephen Warren offers a new theory. Iron oxides, the same compounds that create brown and red rust, are turning icebergs emerald.

If the theory holds, it might do more than solve a riddle. The ice-trapped iron could represent a crucial missing link in the food chain. The icebergs would get the iron during their formation, found in Antarctica's rock dust.

Then the icebergs carry that iron dust out to the ocean, where they could feed phytoplankton, the microscopic organisms that provide nourishment for types of whales, jellyfish, krill, zooplankton, and a variety of other underwater species.

(Image credit: AGU/Journal of Geophysical Research: Oceans/Kipfstuhl et al 1992)

Researchers from the University of Pennsylvania have designed and built millions of functional microscopic robots that can be programmed to do a variety of things. One can only imagine the endless possibilities of what you can do with these tiny robots at your disposal. The researchers will be presenting their work at the American Physical Society March Meeting in Boston.

(Image credit: Marc Miskin)

Different industries in the US are struggling like those in the Rust Belt and quite recently, Steel Valley. General Motors will be ending production in its Lordstown plant which will see 1,700 workers laid off from their jobs.

There were efforts to try and revive the glory days of Steel Valley. They pinned their hopes on the Avanti but the revival didn't come to fruition. Read more on Jalopnik.

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Trying to find a place in the sea of stars in space that could support life is going to be a serious challenge. Scientists say they might have found a good direction toward achieving that goal:

A new study finds a particular class of stars called K stars, which are dimmer than the Sun but brighter than the faintest stars, may be particularly promising targets for searching for signs of life.

Why? First, K stars live a very long time — 17 billion to 70 billion years, compared to 10 billion years for the Sun — giving plenty of time for life to evolve. Also, K stars have less extreme activity in their youth than the universe’s dimmest stars, called M stars or “red dwarfs.”

Of course, K stars aren't the definitive path to finding habitable planets but so far, it is our best bet.

(Image credit: NASA Ames/JPL-Caltech/Tim Pyle)