Science & Tech

A group of researchers has suggested that deep within the Earth are remnants of a planet that once crashed into the Earth, creating the Moon. The results of the research conducted by Dr. Quin Yuan and colleagues were published in Nature.

The propagation speed of seismic waves within the earth varies depending on the density of the environment in which they are located. Seismic waves travel at lower speeds in denser environments. In the 1980s, two regions the size of continents were identified deep within the Earth where seismic waves moved relatively slowly. These regions (LLVPs), one under Africa and the other under the Pacific Ocean, are thought to be more iron-rich and therefore denser than their surroundings.

A group of researchers from the California Institute of Technology has proposed that an iron-rich planet colliding with Earth in the distant past may have led to the formation of LLVPs. Allegedly, LLVPs emerged when some of the remaining pieces of the planet that were torn apart by the impact of the collision were absorbed by the Earth.

The idea puts forward answers yet another question. One hypothesis about how the Moon formed suggests that a Mars-sized planet collided with the Earth in the distant past. According to this hypothesis, the planet called Theia was torn apart by the impact. The remaining pieces of the planet, along with the pieces that broke off from the Earth, formed the Moon over time. If this hypothesis is correct, you would expect to find traces of Theia's remains in places other than the Moon. However, till today, nothing has been discovered that could be Theia's remains. If the source of the LLVPs is a planet that crashed into Earth, that planet could be Theia. It is also known that the Moon is richer in iron compared to the Earth.

The researchers tested their hypothesis with computer simulations. The results suggest that it is possible for the remnants of a planetary collision with Earth to both create LLVPs and contribute to the formation of the Moon. One of the questions that comes to mind regarding the new hypothesis is why the remaining pieces of Theia did not "blend" into the Earth, which was still in the process of forming at the time, but remained in the form of lumps. The computer simulations that have been made also provide an answer to this question. According to calculations, most of the energy transferred to the Earth during the collision remained in the upper half of the mantle. This prevented the lower parts of the mantle from completely liquefying under the impact of the collision. Thus, it was possible for Theia's remains to remain in the earth's crust.

 ***

MICE EMBRYO DEVELOPED IN SPACE:

A group of Japanese researchers sent frozen mouse embryos to the International Space Station (ISS) in August 2021. After being thawed with special devices and grown in microgravity for four days at 37°C, the embryos were seen to continue to develop normally and develop into blastocysts (the early developmental stage of mammalian embryos). The data recorded from the embryo which was sent back to earth showed that there were no significant changes in their DNA and genes.

The results suggest that mammals can continue their lineage in space. It is planned to transplant the blastocysts into mice in the future. If the mice transplanted with blastocysts give birth normally, it will confirm that the embryos grown in space are indeed problem-free.

The results of the study conducted by Dr. Sayaka Wakayama, and colleagues were published in iScience.

 ***

Is Evaporation Possible Without Heat?:

Evaporation, as we know it, occurs through heat transfer: When the molecules within a substance gain enough energy by interacting with their environment, they can manage to detach themselves from the material. However, recent scientific studies show that water molecules can evaporate under certain conditions without receiving heat from their environment.

In recent scientific studies, it has been noticed that the water held in hydrogels can evaporate much faster than expected due to the amount of heat it receives. The evaporation that occurs might not be directly proportional to the amount of heat it receives. A group of researchers tried to study this phenomenon under different conditions. From their study, they explained how this situation occurs and came to the conclusion that evaporation occurs under the influence of light. One of the most important results obtained was that the evaporation rate of water in the hydrogels on which light fell changed depending on the color of the light. This result cannot be explained by the heat effect. In addition, when the experiments are carried out in a light-free environment, keeping all variables the same, the results obtained begin to be compatible with theoretical predictions. This confirms the idea that light is the factor that increases the evaporation rate.

It is surprising that the water in hydrogels evaporates under the influence of light. Because both water and hydrogels have a low light absorption rate. When you look at a lake from above, you see the water deep down because water absorbs very little light. Similarly, hydrogels do not have a high light absorption rate. However, the results obtained show that when these two materials come together, contrary to expectations, the water molecules on the surface of the hydrogel can evaporate with the energy they receive from light.

The ejection of electrons by photons from atoms is called the photoelectric effect. The newly discovered phenomenon, in which photons tear molecules from liquids, was called the "photomolecular phenomenon". It is thought that photomolecular phenomenon can be used in many areas.

For example, the process of obtaining drinking water from salt water is two-staged: First, the salt water is heated to evaporate the water, then the water vapor is condensed to obtain fresh water. The process of obtaining fresh water from salt water can be made more efficient by taking advantage of the photomolecular phenomenon. Another application area of ​​the photomolecular phenomenon could be processes where desiccant materials are used to remove moisture from the environment.

Dr. Yaodong Tu et al., from the Massachusetts Institute of Technology, published the results of the research conducted under the leadership of Prof. Dr. Gang Chen were published in the "Proceedings of The National Academy of Sciences (USA)"