Why do flowers smell? – Henry E., Age 9, Somerville, Massachusetts
Imagine walking through a tropical forest as a sweet scent wafts through the air. A little farther down the path, the putrid stench of rotting flesh makes you catch your breath. Upon investigation, you find that both odors originate from flowers – but why do flowers smell like anything at all?
It’s actually part of a strategy that helps flowering plants reproduce themselves and spread their species. Certain scents help these flowers solve a big problem.
Plants flower to produce seeds that can go on to become new plants. To make a viable seed, pollen from one part of the flower must fertilize the ovules in another part of the flower. Some plants can self-pollinate, using their own pollen to fertilize the ovule. Others require pollen from another plant of the same species – that’s called cross-pollination.
So how does one plant get some other individual plant’s pollen where it needs to be?
Sometimes gravity helps pollen fall into place. Sometimes wind carries it. Wind-pollinated flowers, like those of many trees and grasses, don’t produce a scent.
Other flowers are pollinated by birds, bats, insects or even small rodents carrying the pollen from one flower to another. In these cases, the flowers might provide a little incentive. Animal pollinators are rewarded by sweet energy- and nutrient-rich nectar or protein-packed pollen they can eat.
Flowers that need the help of insects and bats go one step further, producing a floral scent that acts as a smelly kind of welcome sign for just the right pollinator.
An orchid blooming in the tropical forest or a rose in your garden needs to attract a pollinator to bring pollen from flowers of the same species. However, there are flowers which look similar but are from other species. To differentiate itself from other flowers, each species’ flowers puts out a unique scent to attract specific pollinators.
Similar to the perfumes at a department store counter, flower scents are made up from a large and diverse number of chemicals which evaporate easily and float through the air. The type of chemical, its amount and its interaction with other chemicals give the flower its unique scent. The scent of a rose may consist of as many as 400 different chemicals.
People can smell these floral scents because they easily evaporate from the flower, drifting on the air currents to attract pollinators.
Flower fragrances may be sweet and fruity, or they can be musky, even stinky or putrid depending on the pollinator they are trying to attract. A blooming apple or cherry tree emits a sweet scent to attract bumblebees, honeybees and other bees. But stick your nose into the beautiful flowers of a pear tree – a close relative of apples and cherries – and you may recoil in disgust, as these flowers smell musky or putrid to attract flies as pollinators. Similarly, the corpse flower, native to Indonesian rainforests, emits a foul odor reminiscent of rotting flesh to attract flies and beetles to pollinate its flowers.
Moths and bats flying at night locate flowers by the scent some release after the Sun goes down. The night-blooming cereus, the saguaro cactus and the dragon fruit all have large white flowers which open at night – they seem to glow in the moonlight, making them visible to nocturnal visitors. Their strong perfume helps guide pollinators inside. While drinking the sweet nectar, the pollinator picks up pollen which it then deposits in the next flower visited.
Once pollinated, the flower stops producing a floral scent and nectar and redirects its energy to the fertilized embryo that will become the seed.
Republished from The Conversation under creative commons.
Chinese Military Satellite Smashed by Russian Rocket in “Major Confirmed Orbital Collision”
In an incident that is likely illustrative of things to come, Chinese military satellite 1-02 was smashed after it appears to have collided into the debris from a disintegrating Russian rocket.
The collision, which occurred earlier this year, shows the increasing danger of space junk such as satellite parts and other miscellaneous jetsam littering the Earth’s orbit. An estimated 8,000 metric tons of space debris pose the risk of destroying functional equipment such as weather forecasting systems, telecoms and GPS systems – and even manned space travel missions – if the problem isn’t reined in.
The fate of the Chinese satellite was uncovered by Harvard astrophysicist and satellite tracker Jonathan McDowell.
The breakup of Yunhai 1-02 was initially reported by the U.S. Space Force’s 18th Space Control Squadron (18SPCS). However, it wasn’t until recently that McDowell found out what caused the breakup.
The astrophysicist soon found that it was destroyed by space junk that originated from a Russian Zenit-2 rocket that had launched a spy satellite in 1996. On Aug. 14, McDowell found a strange entry in a database on Space-Track.org: “Collided with satellite.”
“This is a new kind of comment entry — haven’t seen such a comment for any other satellites before,” McDowell tweeted.
“A quick analysis of the TLEs show that Yunhai 1-02 (44547) and [the debris object] passed within 1 km of each other (so within the uncertainty of the TLEs) at 0741 UTC Mar 18, exactly when 18SPCS reports Yunhai broke up,” he added, noting that this “looks to be the first major confirmed orbital collision in a decade.”
However, the Yunhai satellite still remains functional and is transmitting radio signals, notes Space.com.
The incident shows the growing likelihood of such collisions in the high-traffic, littered near-Earth orbital zone.
“Collisions are proportional to the square of the number of things in orbit,” McDowell explained. “That is to say, if you have 10 times as many satellites, you’re going to get 100 times as many collisions.”
He added: “So, as the traffic density goes up, collisions are going to go from being a minor constituent of the space junk problem to being the major constituent. That’s just math.”
A worst-case scenario of such collisions is known as the “Kessler Syndrome,” and describes the possibility of one collision setting in motion a chain of collisions. Such a disaster was the premise of the 2013 film “Gravity.”
One hopes that things don’t reach that point.
In the meantime, however, there have been a number of initiatives meant to tackle the growing problem of space debris, such as the ELSA-d spacecraft launched in a demonstration mission earlier this year.
Boston Dynamics Drops New Video Of 5-Foot Atlas Humanoid Robot Effortlessly Doing Parkour
Robot maker Boston Dynamics has released new video of its two-legged Atlas robot effortlessly completing a parkour obstacle course, offering a new display of its humanoid machines’ unsettling repertoire.
In the video, a pair of Atlas robots can be seen leaping over large gaps, vaulting beams, and even performing backflips. The robot can even be seen jumping over a board while using its arm to remain steady.
While the display seems like anything but “free” running – as the original developers of parkour had envisioned – the routine does seem like an impressive, if terrifying, display of effective coding that took months to perfect, according to the Hyundai-owned robotics firm.
“It’s not the robot just magically deciding to do parkour, it’s kind of a choreographed routine, much like a skateboard video or a parkour video,” said Atlas control lead Benjamin Stephens.
See for yourself:
Unlike its robotic dog Spot, which controversially hit New York City streets last year before being pulled, Atlas isn’t a production robot. Instead, it’s a research model meant to see how far the limits of robotics can be pushed.
In the past, Boston Dynamics has displayed the robot’s feats with videos of Atlas jogging and even busting out some cool dance moves.
Team lead Scott Kuindersma said in a statement that in about two decades, we can expect to coexist with robots that move “with grace, reliability, and work alongside humans to enrich our lives.”
Until then, some of us will continue to reserve our right to feel a bit queasy about the prospect of people being chased down by these skilled free-running (and dancing) machines.
South Korean Toilet Turns Poo Into Green Energy and Pays Its Users Digital Cash
What if your morning #2 not only powered your stove to cook your eggs, but also allowed you to pay for your coffee and pastry on the way to class?
It seems like an absurd question, but one university in South Korea has invented a toilet that allows human excrement to not only be used for clean power, but also dumps a bit of digital currency into your wallet that can be exchanged for some fruit or cup noodles at the campus canteen, reports Reuters.
The BeeVi toilet – short for Bee-Vision – was designed by urban and environmental engineering professor Cho Jae-weon of the Ulsan National Institute of Science and Technology (UNIST), and is meant to not only save resources but also reward students for their feces.
The toilet is designed to first deliver your excrement into a special underground tank, reducing water use, before microorganisms break the waste down into methane, a clean source of energy that can power the numerous appliances that dorm life requires.
“If we think out of the box, feces has precious value to make energy and manure,” Cho explained. “I have put this value into ecological circulation.”
The toilet can transform approximately a pound of solid human waste – roughly the average amount people poop per day – into some 50 liters of methane gas, said Cho. That’s about enough to generate half a kilowatt hour of electricity, enough to transport a student throughout campus for some of their school day.
Cho has even devised a special virtual currency for the BeeVi toilet called Ggool, or honey in Korean. Users of the toilet can expect to earn 10 Ggool per day, covering some of the many expenses students rack up on campus every day.
Students have given the new system glowing reviews, and don’t even mind discussing their bodily functions at lunchtime – even expressing their hopes to use their fecal credits to purchase books.