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Comets in the solar system might share the same place of origin

Comets in the solar system might share the same place of origin

According to new research, all comets might come from the same place. Astronomer Christian Eistrup from Leiden University used chemical models on fourteen widely known comets only to find a clear pattern. 

Comets move through the solar system and they are made of dust, ice, and small rocks. Their nuclei can span as wide as several kilometers. Some of them have strange orbits around the Sun and have also hit Earth in the past. Eistrup said that the composition of comets is very well known and are usually considered as icy balls. So he wanted to find out if they actually belong to one group or are divided by several subsets. 

Eistrup’s research team also included Ewine van Dishoeck, Kavli Prize winner who created models for predicting the chemical composition of protoplanetary discs, which are flat discs made of dust and gas encompassing younger stars. These discs help in knowing about the formation of stars and planets. These were now applied to comets. Ewine along with Eistrup used statistics to understand if there was a particular place in the solar system where the models meet the comets’ data. It turned out that all the fourteen comets showed the same result. Each comet could be described by only one model indicating that their common origin. The work can be found here.

The origin is near to our Sun at a time when a protoplanetary disc encircled it while the formation of the planets took place. The model suggests a zone that is farther from the Sun’s nucleus and where the temperature varies in the range of 21 to 28 Kelvin, a very low temperature where CO (carbon monoxide) turns into ice. There are several reactions that are taking place in the ice phase in the time frame of a hundred thousand to million years. This explains different comets with different types of compositions. 

The orbits of the comets vary since some of the comets might have been disturbed by planets like Jupiter, which explains the varied nature of the orbits. 

Eistrup wants to test the hypothesis on many more comets as the current sample size is pretty small, only fourteen. He hopes that astronomers studying the solar system and its origins can use his results which can provide them with new insights, hence he is interested to discuss this model with other comet researchers. 

We still do not how life started on our planet. However, the chemistry of the comets could be responsible for some of life’s building blocks. Life could start with the right comet hitting the right planet accompanied by a suitable environment. Understanding comets could lead to understanding the origin of life on our planet. 


Researchers detect radioactive interstellar dust in the Antarctic Ice

In new research, scientists have found evidence of dust from a nearby supernova under several thousand pounds of Antarctic snow. Our solar system not only comprises of celestial objects such as planets, moon, sun but also a lot of dust that might have originated from the interstellar sources. A group of researchers in Germany, Austria and Australia is in the search of the presence of dust on Earth to understand the circumstances in which the solar system is moving forward. The study has been published in the Physical Review Letters. 

Dominik Koll, first author of the study and a PhD candidate from Australian National University mentioned he is very excited to learn about the stellar explosions and structures present around our planet which have faraway origins. Scientists transported fresh snow which is not more than 20 years old, weighing almost 1100 pounds from the Kohnen Station located in Antarctica to Munich, Germany.

Then the snow was melted in the laboratory, filtered and evaporated for collecting dust and other micrometeorites. Dust was incinerated and put into Accelerator Mass Spectrometer. It is used to create charged ions from the sample, pass through the magnet and then into a particle accelerator before finally sending to a detector. This technique is useful for collecting only specific atomic isotopes. 

The team wanted to find iron-60, a radioactive isotope released by the supernova. It can also have other sources such as the matter irradiated by the cosmic rays. For guaranteeing it to be interstellar dust, researchers also searched for manganese-53 and compared the ratio of iron-60 to manganese-53 to the ratio expected if there was no presence of interstellar dust. A lot more iron-60 was found than expected from the cosmic rays. 

Thomas Faestermann, TU Munich explained that it was previously established that iron-60 was deposited in the solar system by a nearby supernova in the past 1.5 to 3 million years. Its prolonged presence on Earth indicates it is coming from a remaining dust cloud from a supernova.

These studies show better conditions of the interstellar environment through which Sun is travelling. It has been detected that the Sun is in a “Local Bubble” where the density of the interstellar medium is quite less than average possibly due to a recent supernova. It contains the Local Interstellar Cloud which has a higher density than the Bubble. We can know more about these regions from the dust found in Antarctica. 

There are lots of findings remaining as the Antarctic ice could lead an exposition of the history of an ancient supernova. 

Journal Reference: Physical Review Letters. 

nucleus ice freezing

Researchers accidentally discover unique property of crystalline ice

Water ice is not always produced equally. Under specific circumstances, its neat arrangement of lattice molecules in a crystalline fashion get disordered and then it resembles the structure of amorphous solids like glass, plastic.

This was the general idea behind the working however a recent finding has made scientists turn into a confused state.

A specific type of amorphous ice was discovered in the ’80s. It was produced by freezing water to form ice at very extreme temperatures. And immediately this ice was subjected to high amounts of pressure. It was taken that consequent amorphous material was similar to liquid water since water could be frozen to form amorphous ice and then melted back to its previous state. But researchers are not so certain about this anymore.

While trying to study about amorphous ice with very high density, a group of researchers at the Oak Ridge National Laboratory accidentally produced different forms of crystalline ice. Dennis Klug, a material science researcher at the National Research Council of Canada remarked that if the data from the experiment conducted was true then it would signify that the amorphous ice is not connected to liquid water, instead, it is a transformation between two phases which has been interrupted. This is a wide variation from the theory which has been usually accepted. The study was published in Nature.

What actually took place was that the research group planned to study the changes in the amorphous ice with an increase in the temperature. After that, it was considered that the molecules in the disordered state would fall back to the regular ordered lattice with the “melting” of amorphous ice to a crystal form.

Researchers had to first manufacture the amorphous ice. For this, a three-millimeter sphere of heavy water (which has an additional neutron in the nucleus of hydrogen) was frozen. This property of heavy water helps in the analysis of neutron scattering. Next, the temperature was lowered to -173 degrees Celsius and simultaneously the pressure was increased to 28000 times the value at sea level.

When the molecular structure was observed, scientists found that the transformation of ice had taken place through four forms. It started with the regular form and ended up at the form ice XIII, while passing through ice IX and ice XV.

Initially, the team felt that the water sample was not pure. Hence they repeated with another new sample and observed the same result every time. Just by slowly increasing the pressure, scientists had a completely new observation.

The transition of water phase from low-density state to high-density state is thought to occur at a second critical point. However, as per this research, this critical point may not exist. The unexpected results have given scientists a new way to understand the dynamics of water.

helheim glacier breakoff

Scientists declare alarming results of melting glaciers in Greenland

Greenland which is home to the second largest permanent ice sheet has lost ice at a very alarming rate in the past decades. The loss has increased almost six times which can lead to a rise in the sea level as suggested by a research on almost fifty years of data.

The report has been published in the Proceedings of the National Academy of Sciences. It makes an estimate on the loss of ice in Greenland. The figures tell that there has been a loss of 51 billions tons of ice from 1980 to 1990. But this figure has seen a tremendous increase to 286 billion only between 2010 and 2018. Out of the 14 millimetres of rise of sea level which has occurred in Greenland since 1972, half of it has occurred only in the last eight years.

Scientists predict that the worst is yet to come. The areas with the most potential for ice loss, far northwest and northeast of Greenland, which borders the Arctic Ocean have not seen a change like the other areas. If the melting of ice occurs here at a rapid pace, it will lead to the overall loss of ice from Greenland as well as the rise of sea level.

Eric Rignot, a researcher at University of California and NASA remarked that the 1980’s was the time when climate of Earth started to alter in a major way from the natural course due to the emission of greenhouse gases into the Earth’s atmosphere. The melting of ice glaciers in Greenland is a major source of concern when combined with similar loss in Antarctica. The region of Antarctica has also lost ice six times faster than forty years ago, which has been never observed in measurements in the modern era.

West Antarctica has been already affected to a great extent and in addition to that some portions of East Antarctica are also showing ice loss at a major rate. Greenland is home to 200 major glaciers, most of which extend to the ocean rising from thick ice sheets. They flow in the outward direction in narrow submerged canyons.

Most of the ice loss occurs in a steady manner such as in streams of the surface of the ice sheet and also undersea flows. Since Greenland lies in the Arctic Zone which has been warmed by more than two degrees Celsius, there ice loss has increased at a high pace.

There has a rapid change since the last thirty years and humanity has to be ready to face the consequences and we should take actions for preventing the dangerous scenarios.