Whether discovered in nature or man-made, each of these scientific
reversals changes some property in life as we know it. Some of them are
just interesting quirks of nature, while others may have profound
implications for how we’ll live our lives.
10.Time-Reversal Acoustics
We’ve all heard typical echoes, but true sound reversal doesn’t exist
in nature. For example, with exact sound reversal, if you holler
“hello,” it would return as “
olleh,”
with the sound wave traveling precisely toward your mouth instead of
spreading through the air as it typically would. This type of technology
has a lot of uses, such as breaking kidney stones, tracking underwater
vehicles, and translating a speaker to
multiple languages for different listeners.
But one of the most interesting uses would be from a national defense
standpoint. By turning their bodies into homing devices, this acoustic
reversal technology can be used to
stun terrorists
who are scuba diving in the ocean to deliver explosives. One way to do
it would be to magnify and return the sound of their underwater
breathing equipment. The loud noise would make them dizzy and
disoriented. It would probably be painful, too. But the echo would be
delivered so precisely that it wouldn’t harm other people, animals, or
equipment close to the target.
9.Male/Female Genital Reversal
In an evolutionary first for the animal kingdom, scientists have
discovered insects in exceptionally dry Brazilian caves where the
females have penis-like sex organs
called gynosomes and the males have vagina-like structures known as
phallosomes. This is an extreme role reversal between the sexes that
likely includes the females coercing reluctant males into mating for
40–70 hours at a time.
These insects are all from the genus
Neotrogla. Adults are
2.7–3.7 millimeters (0.11–0.15 in) long. The gynosomes, or female
penises, are approximately one-seventh as long as the insects. That’s
like a man with a height of 175 centimeters (5’9″) having a penis that’s
almost 25 centimeters (10 in) long.
After inserting her gynosome into the male’s phallosome, the female
Neotrogla‘s
sex organ balloons with a spiny covering to anchor itself tightly to
her mate. The long copulation period allows a greater transfer of semen
from the male.
Researchers seemed to be particularly interested in how male
Neotrogla
would react to coercive mating, which is another unusual role reversal
in these species of insects. With other species, coerced females will
get rid of semen from males they don’t like, or they’ll deliberately
receive sperm from other males they do like. But the
Neotrogla
males don’t receive eggs from their mates, so they don’t have a way to
retaliate, especially since the spines on the female gynosome bind them
together.
8.The One-Way Sound Machine
All sound waves possess a property called “time reversal symmetry.”
If you send a sound wave through the air in one direction, it can be
returned the same way. So if you can talk to someone, they can talk back
to you, and each person will hear the other.
Time reversal symmetry also works with other waves, including visible
light and radio waves. With radio waves, however, scientists discovered
how to spin electrons in only one direction using magnetic materials.
This breaks time reversal symmetry, so that the radio waves broadcasting
our favorite songs won’t bounce back to the transmission towers.
Until recently, though, scientists didn’t know how to control the
direction of sound waves through the air so that you could hear without
being heard. They wanted to create a sound wave version of a one-way
mirror, which would be a great way to
spy on people. Not surprisingly, this research was funded by the US government.
Using those funds, a team from the University of Texas at Austin devised an ingenious solution. They built an
acoustic circulator,
a device that’s like a starfish with three arms. The arms are pipes
with microphones at the end to record sound that flows through a
ring-shaped cavity in the central body. Three fans in the cavity operate
at a speed that makes sound move in one direction only.
So if you were to embed a wall with several of these circulators, you
could hear the activity on the other side without anyone hearing you.
These devices can insulate sound in airplanes, music studios,
submarines, and more. They can also make sonar and ultrasound machines
more accurate.
7.Unboiling An Egg
In a process that takes only minutes, scientists have figured out how
to unboil egg whites. They added urea, a major component of urine, to
dissolve the egg whites, and then they spun the resulting liquid mixture
at high speed in a vortex fluid device. But they didn’t do it so you
could change your breakfast order from boiled eggs to scrambled or once
over easy without cracking new eggs. Instead, this discovery has the
potential to transform manufacturing processes that may reduce the costs
of cancer treatment and food production.
The scientists started by boiling egg whites at 90 degrees Celsius
(194 °F) for 20 minutes to make them extremely hard. This causes the
individual proteins in the gooey transparent egg whites to become
tangled messes within the boiled egg whites. “That process is called
‘aggregation,’ ”
said researcher Gregory Weiss from the University of California,
Irvine. “This drives us nuts, as scientists, because it’s really hard to
disentangle [the proteins] later. Oftentimes, we have this protein that
we want to study, and it comes out, and they’re just goo.”
Other than demonstrating how this process works, the hen eggs are
actually irrelevant. As Weiss explained, “The real problem is there are
lots of cases of gummy proteins that you spend far too much time
scraping off your test tubes, and you want some means of
recovering that material.”
Using their procedure, the scientists can gently untangle the proteins
much faster and more cheaply than previous methods, which took about
four days. This is important for any biotechnology company that needs to
fold proteins.
6.Reversal Of Emotional Links To Memories
We’ve previously discussed how scientists genetically altered the
individual brain cells of mice so that a beam of light would switch
cellular activity on and off. This technique is called optogenics. In
their first experiment, researchers planted
false memories
in the brains of these mice then triggered recall of those memories
with a beam of light. Now, scientists are taking optogenics to the next
level by altering the emotional content of a memory. They can turn a
negative association with a memory into a positive one and vice versa.
Each memory has components that are stored in different areas of the
brain. For example, the context of a memory (such as where something
happened) is stored in the brain’s hippocampus, while the emotional part
of that memory is retained in the amygdala.
To test if they could change the emotion linked to a memory of being
in a specific location, the researchers gave male mice either the
positive experience of meeting a female mouse or the negative experience
of receiving a small electrical shock. Then scientists moved the mice
to a new location and used a beam of light to trigger that memory. But
this time, each mouse received the opposite emotional experience. The
male mice who first had the pleasure of meeting females now got shocked
when that memory was triggered, and the male mice who were originally
shocked got the girls this time around.
Based on how the mice reacted once back in the first location, it
appeared that the emotions linked to the memory had changed. For
example, mice that were originally shocked were less afraid in that same
location and began looking for a female mouse.
However, it only worked if they activated the brain cells in the
hippocampus, where the context of the memory was stored. It didn’t work
if they activated brain cells in the amygdala, where the emotion
associated with a memory was located.
5.Reversal Of Individual Continents Into A Supercontinent
The last supercontinent was Pangaea, when dinosaurs were roaming the
Earth. Before that, three or four other supercontinents had formed
during our planet’s multibillion-year history.
Scientists know that Earth’s continents move continuously, slowly
drifting together and breaking apart like puzzle pieces because they
rest on shifting tectonic plates. “Continents on these plates typically
move . . .
at the rate your fingernails grow,” said Ross Mitchell of Yale University. So it can takes hundreds of millions of years for a new supercontinent to form.
That hasn’t stopped scientists from making predictions about the new
supercontinent, even though humans probably won’t be around to see them
come true. In possibly 50–200 million years from now, some scientists
predict the next supercontinent will be Amasia, the melding together of
the Americas and Asia. But where will this supercontinent form?
The first theory, introversion, says that Amasia will close up the
Atlantic Ocean to form where Pangaea once rested along the equator. The
second theory, extroversion, says that Amasia will close the Pacific
Ocean to form a supercontinent along the equator on the other side of
the world.
However, a more recent theory of introversion says that new supercontinents
always form at right angles
to their predecessors. With the continents appearing to drift
northward, Amasia will form at the North Pole by closing the Arctic
Ocean and the Caribbean Sea. By analyzing the magnetic signature of
ancient molten rocks, which freeze into place pointing north like a
compass, researchers can determine how these rocks have shifted over
time and where the land masses will move to form the next
supercontinent. Their theory is consistent with Pangaea being at a right
angle to where its predecessor, Rodinia, split apart. Rodinia, in turn,
formed at a right angle to its predecessor, Nuna.
More importantly, the location of these supercontinents can help us
to understand where life emerged at different points on our planet and
how it moved over land masses. “Continents with similar fossil records
likely share an evolutionary ancestry,” said Mitchell, “but actually
establishing a land bridge by juxtaposing those continents is finding
the smoking gun.”
4.Evolutionary Reversal Of The Osedax
We previously discussed
Osedax mucofloris (similar to the Annelid pictured above), the “
bone-eating snot flowers.”
These red zombie worms, each about an inch or two long, burrow into
the bones of dead whales and secrete acid to feed off of them. Then
researchers discovered that all of the worms in the whale bones were
females. Scientists didn’t find the males until they examined a female
under a microscope. Living within the tubes of the females were larval
dwarf males, each approximately 1 millimeter long. Every female
contained a harem of 30–100 individual males.
“These males don’t feed,” said biologist Robert Vrijenhoek. “A male
lives its entire life off the yolk that was provisioned by the egg from
which it hatched. This is one of the few cases in the animal world
where sexually reproducing individuals are
barely more developed than eggs. It’s weird.”
But it became even more weird when scientists discovered a new species of
Osedax
whose males had reverted to an ancestral state. In this species, the
females were about the same size as the females of other known
Osedax species. However, the males of the new species were about as large as the females. These males were
tens of thousands of times bigger than normal.
Scientists were surprised by this evolutionary reversal because they
believed the genes to create full-size male adults had disappeared from
lack of use. Unlike their dwarf counterparts, these full-size males feed
on bone themselves.
Scientists named this species
Osedax priapus, after the
fertility god in Greek mythology because the males’ bodies appear to
have evolved for mating purposes. Dwarf males don’t have to go anywhere
to mate because they’re permanently attached to the females’ bodies. But
the larger
Osedax priapus males can extend their bodies up to 10
times their normal size to find mates. Scientists aren’t sure, but they
believe that the larger
Osedax priapus males evolved because there were fewer
Osedax females competing for space on some animal bones.
3.Reversal Of Cellular Aging
We’ve previously discussed the
immortal jellyfish,
Turritopsis nutricula,
which can revert to an immature stage of development if it becomes
damaged. If humans could do this, adults would be able to revert to
babies as needed to escape the ravages of disease. We’ve also talked
about how the
infusion of young blood into mice reversed aging in these animals. Whether this would work for humans is the next stage of testing to be done.
One study out of the University of California at Berkley looked at
reversing cell degeneration by injecting cells in mice with SIRT3, a
protein that regulates aging. “Aging is just an accumulation of damage,”
said lead researcher Danica Chen. “If you think that way, then it’s
probably not reversible, because cells are already damaged and no longer
functional. But what we show here is that
oxidative stress-induced damage,
in fact, is reversible.” This damage occurs because older people don’t
channel and use oxygen in their bodies as efficiently as younger people,
resulting in aging.
This isn’t about producing a fountain of youth. Its practical
application would be to prevent and treat age-related degenerative
diseases like arthritis, Alzheimer’s, and heart disease. SIRT3 also
appears to suppress tumors. Normally, anything that would regenerate
cells would cause cell division and increase the risk of cancer. SIRT3
appears to reverse damage at the molecular level. Of course, we don’t
know how well it will work in humans, especially long-term. This is the
first study to show that we can reverse cellular aging, not just slow it
down.
In a separate test, Stanford researchers were able to
lengthen the telomeres
of human skin cells, which reverses time (and aging) on the telomere
clock, giving those cells a longer life. Telomeres are the repeating DNA
sequences at the end of chromosomes. The eventual goal for this
technique is to treat diseases that result from shortened telomeres.
2.Reversal Of The Doppler Effect
The Doppler effect describes the
change in frequency
of sound waves or light as you get closer to or farther away from the
source. A common example is the change in pitch of an ambulance siren or
train whistle, which sounds higher as it comes closer to you (as the
frequency increases) and lower as it moves farther away (as the
frequency decreases). By reversing the Doppler effect, we can start to
create
acoustic cloaking technology.
In 2011, scientists first reversed the optical Doppler effect, which is necessary to develop
invisibility cloak technology.
When we see an object, we’re really seeing its reflected light. So for
an object to become completely invisible, we’d have to bend all
wavelengths of visible light around it so that it
produces no reflection and casts no shadow.
To bend light around an object, that object must have a
negative refractive index.
Light waves bend backward instead of moving forward through the object.
This doesn’t occur in nature. We have to create artificial materials,
called metamaterials, to control the path of light.
Materials with a negative refractive index also reverse the Doppler
effect. Normally, as an object comes closer to us, the frequency of
light increases, shifting the wavelengths toward the blue end of the
spectrum. With a reverse Doppler effect (which doesn’t occur in nature),
the frequency of light decreases, shifting the wavelengths
from blue to red as an object comes closer and from red to blue as it moves farther away.
This scientific reversal could change the world in many ways. We’ve already discussed some of the cloaks for
light, sound, touch, and thermal signature that are being developed or are already available with today’s technology.
1.The Chickenosaurus
Paleontologist Jack Horner, once a technical adviser for
Jurassic Park,
is hard at work trying to create a chickenosaurus. In 2009, he made a
media splash with the claim that he intended to manipulate chicken genes
to revive some
latent dinosaur traits.
From an evolutionary standpoint, modern chickens are part of the
velociraptor line of dinosaurs which had feathers when they lived from
71 to 86 million years ago.
With a maximum weight of 15 kilograms (33 lb), velociraptors were
small bird-like dinosaurs that could grow to a length of almost 2 meters
(7 ft) and a height of 0.5 meters (1.6 ft) at their hips. Although
their arms were too short for flying, their feathers suggest that their
ancestors were once able to fly. This carnivorous dinosaur had a narrow
snout with about 30 serrated teeth in its jaws, a tail, and two arms
that ended in hands, each with three curved claws.
It’s these features—the
teeth, tail, and arms—that
Horner wants to reverse-engineer from a chicken by switching on or
suppressing the appropriate genes. So the chicken’s beak would become a
dinosaur’s snout with teeth, the tail would be reactivated, and the
chicken’s wings would become arms, possibly with hands and claws. This
animal wouldn’t be a dinosaur but rather a modified chicken with
dinosaur characteristics.
Horner believes this experiment would teach people about evolution.
It may also have medical applications as we discover what happens when
genes are switched on and off. But the initial problem was
locating the appropriate genes
to reactivate dinosaur features in a chicken. So far, the research team
has studied the development of tails in chicken embryos, which are
then reabsorbed.
