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Scientists find a new way to measure gravity
Researchers develop a novel method to measure gravity that can get much more information.
- Scientists use lasers that suspend atoms in air to measure gravity.
- This method can be more precise and allow for gathering of much more information.
- Portal devices using this technique can help find mineral deposits and improve mapping.
You drop something and it falls. That's how you know there is gravity, right? Scientists at the University of California, Berkeley, improved upon this age-old test to find a new and potentially more useful way to measure gravity using lasers suspending atoms in midair.
The usual approach to measuring gravity involves making something fall, preferably in a long shielded tube or tower, and then measuring it as it flies by with an instrument. While this classic method connects to our everyday experience of gravity, it has limitations. For one, the opportunity to understand gravitational effects is very brief during such a test. There are also other forces, like magnetic fields, at play, possibly affecting the results.
The new technique developed by a team of researchers, led by physicist Victoria Xu, doesn't rely on making anything fall. Instead it pinpoints the differences in atoms in a superposition state.
Superposition is the physics principle that says a system can be in multiple states until it's measured.
What the researchers figured out is a process that starts by releasing a cloud of cesium atoms in a small chamber. Then they used flashing lights to split some of them into superposition states. Once the atoms were taken apart in this way, lasers were employed to keep them in fixed positions.
One atom in each pair was suspended a few micrometers higher than the other. This allowed the scientists to measure the wave particle duality of each atom's wave as it was being affected by gravity.
"Atoms in a spatially-separated quantum superposition are suspended against Earth's gravity, using the standing wave formed by an optical cavity. "
Wave particle duality is the quantum mechanics idea that every particle can act as a particle or a wave.
Measuring differences in duality between the atoms in a pair, with each one being at a varying distance from Earth, allowed the researchers to quantify the effects of gravity on the atoms.
The advantage of this technique is that it can potentially help gather a lot of new information, with implications for a wide range of fields, even the search for dark matter. Not having the atoms zipping through the air aids in the collection of significantly more precise measurements of gravity as well as the gravitational attraction between objects and more.
It is also easier to protect these much smaller measuring devices from interfering magnetic fields.
Another cool thing - this type of approach makes it easier to create portable gravity-measuring devices. That way they can be taken to different places on Earth to look for mineral deposits and for improved mapping.
"Laser light (purple) shines into our ultra-high vacuum chamber to laser-cool atoms to less than half a millionth of a degree above absolute zero. A pair of mirrors mounted inside the vacuum chamber enhance flashes of light which kick, suspend, and interfere the atoms. "
The study's co-author Holger Müller laid out some of the benefits:
"Let's say you don't want to measure the gravity of the entire Earth, but you want to measure the gravity of a small thing, such as a marble," he said to Science News. "We just need to put the marble close to our atoms [and hold it there]. In a traditional free-fall setup, the atoms would spend a very short time close to our marble — milliseconds — and we would get much less signal."
The initial reviews on the study were positive, with physicist Alan Jamison of MIT calling it "very impressive."
Check out the new study "Probing gravity by holding atoms for 20 seconds" in the journal Science.
This storm rained electrons, shifted energy from the sun's rays to the magnetosphere, and went unnoticed for a long time.
- An international team of scientists has confirmed the existence of a "space hurricane" seven years ago.
- The storm formed in the magnetosphere above the North magnetic pole.
- The storm posed to risk to life on Earth, though it might have interfered with some electronics.
What do you call that kind of storm when it forms over the Arctic ocean?<iframe width="730" height="430" src="https://www.youtube.com/embed/8GqnzBJkWcw" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> Many objects in space, like Earth, the Sun, most of the planets, and even some large moons, have magnetic fields. The area around these objects which is affected by these fields is known as the magnetosphere.</p><p>For us Earthlings, the magnetosphere is what protects us from the most intense cosmic radiation and keeps the solar wind from affecting our atmosphere. When charged particles interact with it, we see the aurora. Its fluctuations lead to changes in what is known as "space weather," which can impact electronics. </p><p>This "space hurricane," as the scientists are calling it, was formed by the interactions between Earth's magnetosphere and the <a href="https://en.wikipedia.org/wiki/Interplanetary_magnetic_field" target="_blank" rel="noopener noreferrer">interplanetary magnetic field,</a> the part of the sun's magnetosphere that goes out into the solar system. It took on the familiar shape of a cyclone as it followed magnetic fields. For example, the study's authors note that the numerous arms traced out the "footprints of the reconnected magnetic field lines." It rotated counter-clockwise with a speed of nearly 7,000 feet per second. The eye, of course, was still and <a href="https://www.sciencealert.com/for-the-first-time-a-plasma-hurricane-has-been-detected-in-space" target="_blank" rel="noopener noreferrer">calm</a>.</p><p>The storm, which was invisible to the naked eye, rained electrons and shifted energy from space into the ionosphere. It seems as though such a thing can only form under calm situations when large amounts of energy are moving between the solar wind and the upper <a href="https://www.reading.ac.uk/news-and-events/releases/PR854520.aspx" target="_blank">atmosphere</a>. These conditions were modeled by the scientists using 3-D <a href="https://www.nature.com/articles/s41467-021-21459-y#Sec10" target="_blank">imaging</a>.<br><br>Co-author Larry Lyons of UCLA explained the process of putting the data together to form the models to <a href="https://www.nbcnews.com/science/space/space-hurricane-rained-electrons-observed-first-time-rcna328" target="_blank">NBC</a>:<br><br>"We had various instruments measuring various things at different times, so it wasn't like we took a big picture and could see it. The really fun thing about this type of work is that we had to piece together bits of information and put together the whole picture."<br><br>He further mentioned that these findings were completely unexpected and that nobody that even theorized a thing like this could exist. <br></p><p>While this storm wasn't a threat to any life on Earth, a storm like this could have noticeable effects on space weather. This study suggests that this could have several effects, including "increased satellite drag, disturbances in High Frequency (HF) radio communications, and increased errors in over-the-horizon radar location, satellite navigation, and communication systems."</p><p>The authors <a href="https://www.nature.com/articles/s41467-021-21459-y#Sec8" target="_blank" rel="noopener noreferrer">speculate</a> that these "space hurricanes" could also exist in the magnetospheres of other planets.</p><p>Lead author Professor Qing-He Zhang of Shandong University discussed how these findings will influence our understanding of the magnetosphere and its changes with <a href="https://www.eurekalert.org/pub_releases/2021-03/uor-sho030221.php" target="_blank" rel="noopener noreferrer">EurekaAlert</a>:</p><p>"This study suggests that there are still existing local intense geomagnetic disturbance and energy depositions which is comparable to that during super storms. This will update our understanding of the solar wind-magnetosphere-ionosphere coupling process under extremely quiet geomagnetic conditions."</p>
Research reveals a new evolutionary feature that separates humans from other primates.
- Researchers find a new feature of human evolution.
- Humans have evolved to use less water per day than other primates.
- The nose is one of the factors that allows humans to be water efficient.
A model of water turnover for humans and chimpanzees who have similar fat free mass and body water pools.
Credit: Current Biology
Being skeptical isn't just about being contrarian. It's about asking the right questions of ourselves and others to gain understanding.
- It's not always easy to tell the difference between objective truth and what we believe to be true. Separating facts from opinions, according to skeptic Michael Shermer, theoretical physicist Lawrence Krauss, and others, requires research, self-reflection, and time.
- Recognizing your own biases and those of others, avoiding echo chambers, actively seeking out opposing voices, and asking smart, testable questions are a few of the ways that skepticism can be a useful tool for learning and growth.
- As Derren Brown points out, being "skeptical of skepticism" can also lead to interesting revelations and teach us new things about ourselves and our psychology.