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Summary of the year 2014 Part II - Astronomy and astrophysics: a rare meeting between Mars and the comet 'Ben David' of the Earth and a supercluster

The science websites summarize the year 2014 also in the field of space exploration, starting with discoveries in our solar system and other solar systems and also new insights into our position in the universe, about dark matter and also a controversial discovery regarding what is considered to be the remains of the inflation after the big bang

Comet Siding Spring as it might have been seen from Mars. Figure: Indian Space Agency
Comet Siding Spring as it might have been seen from Mars. Figure: Indian Space Agency

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The planet Mars experienced a rare close transit of a comet in 2014. The comet, named Siding Spring (after a city in Australia whose observatory was discovered) passed at a distance of 140 thousand kilometers from the surface of Mars (less than half the distance between the Earth and the Moon) and left behind showers of dust and probably many other atmospheric phenomena.

The five satellites orbiting Mars were aligned to be on the far side of Mars when the comet approached, which was a smart move because the comet spewed several tons of material onto the planet, much more than scientists expected.
Despite this, the spacecraft were able to study the impact of dust deposition that literally changed the Martian atmosphere. According to the scientists, the dust contains high levels of sodium, which probably colored the sky yellow when the dust particles entered the atmosphere and burned up. Traces of iron, zinc, potassium, manganese, nickel and chromium were also discovered in this dust. The dust also contained high levels of magnesium, which was noticed due to the fact that this element was rare in the Martian atmosphere before the encounter.


The approach of a comet to Mars is an event that occurs on average once every 8 million years, and we have a lot of research ahead of us and it will take at least another year for the results to arrive.

A planet the size of Earth and in the habitable zone

Kepler 186f is the first Earth-sized planet orbiting its Sun in the habitable zone, and is referred to as "Earth's cousin". Since in the orbit where the planet is, water is kept in a liquid state, it may support life for which water is an essential commodity for its existence.

Kepler 186f is less than 10% smaller than Earth. It surrounds a red dwarf. Red dwarfs are smaller and dimmer stars than our sun, and therefore their habitable zone is much closer to that of the solar system.

Kepler 186, the parent star of Kepler 186f is about 490 light years from Earth. It is believed to be a liquid planet but it is not yet known if it has an atmosphere suitable for life. As planets become more massive they become more like gas giants like Jupiter than terrestrial planets like Earth and Mars.
The Kepler space telescope has lowered its activity levels due to malfunctions in the stabilization systems and therefore can be used to a limited extent, but even so it has already managed to discover a super-Earth-type planet. But the glitch was enough for the scientists to announce the discovery of about 700 new planets outside the solar system, and about two thousand more 'planet candidates' that still need to be monitored by ground telescopes.

Artist's rendering of the planet Kepler-186f, the first Earth-sized planet orbiting its sun in the habitable zone, one of the astronomical discoveries of 2014. Image: NASA Ames Center, STE Institute, JPL-Caltech
An artist's drawing of Kepler-186f, the first Earth-sized planet orbiting its sun in the habitable zone, one of the astronomical discoveries of 2014. Image: NASA Ames Center, STE Institute, JPL-Caltech

"The ultimate goal of the search for Earth-like planets is to find out whether we are alone or not?" said Tom Berkeley, a NASA scientist who is a member of the Kepler mission and one of the researchers who discovered the planet. "To answer this we need to first answer smaller questions, are there other places that could contain extraterrestrial life. With the discovery of f186 the answer to that question is yes, he said.

A subsurface ocean on Enceladus and evidence for plate tectonics on the moon Europa

An ocean is hidden beneath the ice covering the moon Enceladus. Does it contain life?

In 2005, NASA's Cassini spacecraft captured images showing plumes of water vapor being emitted from cracks called "tiger stripes" near the south pole of Enceladus, one of Saturn's icy moons.

These images alone failed to prove the existence of liquid water below the surface of the moon. But in April of this year, an analysis of gravity measurements taken by Cassini confirmed that a large reservoir of liquid water exists beneath Enceladus' icy outer mantle. Furthermore, they confirmed that the tiny moon consists of two layers - an outer ice layer and an inner rocky core composed of silicates. A combination of silicates and liquid water means that Enceladus contains an environment with the potential for life, and it may even be friendlier to it than Jupiter's moon Europa.
Four months later, members of the Cassini team presented observational data from which it can be concluded that the geysers discovered on Enceladus may be directly connected to the ocean that lies beneath its surface.

Carolyn Fork, head of Cassini's imaging team, said: "For me, the discovery of a habitable environment inside Enceladus was Cassini's most profound discovery. Many of us are now asking whether there is a second source of life in the Solar System, and precisely on this small moon. "

In September, researchers published evidence suggesting a system of tectonic plates capable of moving in ancient regions on the surface of the moon Europa, which lie beneath adjacent plates. If confirmed, the finding, Europa would be the only place in the solar system (other than Earth) whose surface continues to be shaped by active tectonic plates.

An underground ocean also on Earth that contains an amount of water equal to that of the surface oceans

After a series of experiments, geologists have come to the unsurprising conclusion that there is a large ocean of water deep beneath the Earth's crust, trapped within a high-pressure zone within the mantle—the region that separates our planet's liquid metal core from its outer crust.

For decades, geologists have hypothesized about the origin of the water in the oceans. The most popular theory today is that ice comets collided with the Earth, melted and filled what later became the oceans, but another theory, which now seems more plausible, was that the Earth was already full of water when it was formed. When the planet formed from dust and rocks, some of the water rose up, according to the surface and another, quite large part was trapped in various rocks under the crust.

The Laniakea cluster. Screenshot from a Nature YouTube video
The Laniakea cluster. Screenshot from a Nature YouTube video

New insights into our place in the universe.

A new cosmic map gives scientists an in-depth look at the boundaries of a giant supercluster that is home to our own Milky Way galaxy and many more. The scientists even named this group Laniakea - boundless sky in the native Hawaiian language. The galaxy cluster in which the Milky Way is also found is 100 times larger in volume and mass than previously thought. Astronomers using an innovative mapping technique have revealed a vast region of interconnected galaxy clusters.

"We live in a kind of cosmic network where the galaxies are connected in a kind of tendrils separated by empty spaces in space" says the lead researcher, Brent Tully, an astronomer at the University of Hawaii in Honolulu.
The 100D map developed by Tully and his colleagues shows that the Milky Way lies at the edge of the Anikea cluster, which consists of about 520 galaxies, is about 100 million light years in diameter, and has a mass of XNUMX million billion solar masses.

The new study better defines the boundaries separating the clusters and offers a completely new perspective on our galactic environment.

Has dark matter been discovered?

2014 may be remembered as the year when dark matter was first discovered.
Researchers examining data from the European Space Agency's XMM-Newton spacecraft have discovered mysterious X-rays (X-rays) coming from both the Andromeda galaxy and the Perseus galaxy cluster. It does not appear to be related to any known material, and the researchers say that one of the possible explanations is dark matter.

Until now, scientists have never discovered evidence of the existence of dark matter. It does not emit, reflect or absorb light (hence its name - "dark" material). However, the scientists estimate that the dark matter makes up about 80% of all the matter in the universe, and it exerts gravitational forces on the normal matter of which the stars and galaxies are composed. The XMM-Newton findings did not get the attention from the scientific community that one would expect from the discovery of the century. The researchers say there are still alternative explanations for the mysterious signals.

Scientists don't know what dark matter is made of, but there are many candidate particles. The new findings indicate that the dark matter may be composed of the axion particle. Other dark matter researchers are looking for a particle known as weakly bound massive particles or . WIMPs.

This year three experimental projects were started that will locate the dark matter and use sensors 10 times more sensitive than the existing ones.

Evidence for the Big Bang that has been disproved in the meantime

In March, researchers from Harvard presented on the discovery of clues to gravitational waves. Using a detector at the South Pole, they observed a particular pattern in the cosmic background radiation, indicative of B-mode gravitational waves, which theoretical cosmologists predicted would peak during the first minus 34 seconds after the Big Bang. or so they thought.
Shortly after the publication of the study, scientists suggested that the origin of these gravitational waves was in the interstellar dust. The researchers promised to watch the massive telescope in the Antarctic BICEP2 to find gravitational waves in areas where the cosmic dust around the Earth is thinner.

The discovery made by the BICEP2 partnership grabbed world headlines when its people claimed to have discovered evidence of the rapid expansion or inflation of the universe after the Big Bang, which caused ripples in the fabric of the universe. In September, an external study cast great doubt on the findings.
BISEP2 (Background Imaging of Cosmic Extragalactic Polarization)) uses a telescope in Antarctica to discover the light created by the big bang known as the cosmic background radiation in the microwave field. Patterns that are very difficult for you can indicate that the universe expanded immediately after the big bang and that the inflation created gravitational waves or ripples in space-time.
In September, scientists working with the European Space Agency's Planck satellite, who also examined the cosmic background radiation, announced that BICEP2's interpretation of a pattern in the light may be nothing more than gas and dust in the Milky Way. The greatest cosmological discovery of the 21st century is about to collapse.
The two teams are currently comparing their data to issue a more definitive statement about the findings. It is still possible that BICEP2's initial interpretation is correct.

Year summaries in astronomy:

10 תגובות

  1. Yehuda,

    I'm glad you liked the sentence. What are your feelings regarding the sentence "You received links to articles providing numerous evidence and testimonies in favor of dark matter but you refused to read them, saying that if you read them anyway you would not understand because they are in English and are dozens of pages long"?

    Nice sentence too, isn't it?

  2. Albenzo:
    The answer is not to collapse the idea I conveyed about dark matter, and not as ego versus ego. I respect your opinion.
    Envy of writers breeds wisdom, and no doubt from your answer you understand something on the subject.
    + To remind you, Einstein did not receive a Nobel Prize for the theory of relativity, and Hawking did not receive a Nobel Prize.
    Edward Witten did not receive a medal in physics for finding an additional dimension in string theory and laws of duality between the various particles, but a Fields medal in mathematics for manifold surfaces.
    Emerging theories are not rewarded in physics, but indirectly. The time constant of verifying theories in physics is long.
    Verlinda received the Spinoza Prize for his overall contribution. Would it have been accepted without gravitational entropy? Maybe.
    + The grant awarded to Verlinda (the spelling is not accurate, but it is not relevant to physics) is used by him to promote the theory.
    As fate would have it, it was precisely in China that the next leap was made and it is real.
    + Entropic gravity produces gravity that does not need dark matter.
    The name "Modified entropic gravity revisited" is from an article by Tower Wang from 2012 and from another article published by Springer Worlag from September 2014 in a Chinese newspaper and not a book as I said.
    This publication does not put out fancy theories for sale.
    + True, it is appropriate to separate Verlinda's algebra and entropic gravity.
    I agree. These are two separate works.
    + Entropic gravity according to Verlind, is not relativistic. Gravity is achieved there from the entropy of particles with no inherent force.
    In the introduction to the article published by Verlind it is said:
    Inspired by Verlinde's idea, some modified versions of entropic gravity have been suggested. Extending them in a unified formalism, here we derive the generalized gravitational equations accordingly. the energy-momentum conservation law and cosmological equations are investigated. The covariant conservation law of energy-momentum tensor severely constrains viable modifications of entropic gravity. A discrepancy arises when two independent methods are applied to the homogeneous isotropic universe, posing a serious challenge to modified models of entropic gravity.

    That is, generalization to gravity equations. The cosmological constant is in the equations of general relativity.

    Regarding the misplaced comparison. I don't agree. There are 2 theories - one holds that the gravity resulting from general relativity does not match the observations and there is still about 90(%) matter in the universe that has not been discovered from particles unknown to us.
    The second holds that gravity as we know it in short ranges is not correct and requires a correction and by the correction there is not necessarily a need for dark matter. Why is the first theory superior to the second?

  3. I liked the sentence: "Dark matter (a theory that has been studied in depth, has mountains of theoretical and observational evidence)"
    Blessed is the believer.
    good week

  4. Joseph,

    Your mistakes have been explained to you more than once and twice in the past. To explain to you again that entropic gravity is a beautiful idea with zero scientific importance, because it simply does not advance us anywhere and does not even attract research work that is close to significant? It's been years since nobody did anything about this, more or less since the idea was first proposed? All this has already been explained to you and you choose to ignore it. OK, you probably have some obsession with this idea that leaves you blind to reality if it doesn't line up with your views.

    But Rabak, at least don't distort and reinvent the facts! Below is a list of facts (which are not my opinions, and you can check them yourself) that is distorted in your response, some are important and some are completely insignificant and are known only for good measure. All of them have already been brought to your attention before.

    1. The physicists name is not Verlind, but Verlinde. The last syllable must be pronounced, they are not American.

    2. Entropic gravity never "won the Spinoza prize" as you claim. Eric Verlinda won the Spinoza Prize and not for a particular work. In the official press release there was no mention of entropic gravity. In the committee's deliberations you can find a mention of all the works Verlinda has done since his doctorate (that is, over more than 20 years) and they also include entropic gravity. I previously gave you the example: to say that Eric Verlinda won the Spinoza Prize because of the idea of ​​entropic gravity is like saying that Gandhi won the Nobel Peace Prize because he reconciled a quarrel between his neighbor and his wife (and also led a non-violent coup for freedom and human rights). ridiculous.

    3. Both twins Verlinda are physicists.

    4. The algebra you speak of, Verlinde algebra, is in no way related to entropic gravity. It is considered Eric Verlinda's most significant achievement and is related to string theory (provides powerful computational tools for the string world sheet). Again - it has nothing to do with entropic gravity nor with general relativity. This is a work that is more than 30 years old.

    5. Entropic gravity does not state that we do not need dark matter. The idea has been proposed and is interesting, but not enough work has ever been done to show that cosmological or dynamical results can be explained without dark matter.

    6. There is no such thing as "the unification of entropic gravity" with general relativity. Entropic gravity talks about reconstructing Einstein's equations from entropic considerations. Nothing to do with general relativity.

    7. Wang didn't do anything even close to what you said. In fact, he did just the opposite. He tested consistency conditions for theories of entropic gravity and discovered that there are very strong constraints on theories of this form. That is, almost all the theories that can be built according to this idea are inconsistent. Specifically, the theory that reproduces Einstein's equations (presented by Verlinda in the original article) is indeed consistent, but on the other hand - we know that Einstein's equations are not the full picture. They are only an approximation of the true description of gravity, which must have quantum corrections.

    8. Trying to present dark matter (a theory that has been studied in depth, has mountains of theoretical and observational evidence) and entropic gravity (no evidence, a tiny number of papers over a period of more than 5 years) as two equal possibilities, neither of which is certain, is simply ridiculous. It's like saying that I don't know for sure, it could be that the reason I'm sick is that I was attacked by a bacterium that entered my body through something I ate or maybe inhaled it, and it could also be that I was kidnapped by the CIA who injected me with an experimental virus and erased my memory. Both are uncertain possibilities that need to be tested... and I'm not trying to say that entropic gravity is a crazy or ridiculous idea, it's just that sometimes there are two possibilities that are both uncertain, but one is a little more likely than the other, and presenting them as equal is simply absurd.

  5. The interesting news about Mars is that it is easy to influence its atmosphere. So if they wanted to heat it up to make it suitable for human habitation, it seems possible.

  6. It is enough to look at the number of conferences on the subject of modified gravity during 2014-2015 to understand that a non-marginal stream has emerged in physics that is trying something different. modified gravity has been active for about 20 years, but in the shadows, without the ability to compete with dark matter. The theory of entropic gravity and its union with general relativity give physical content to what was previously an educated guess.
    Gravity is a force created simply by a local non-uniform distribution of matter in space. So there was a willingness in the Netherlands to finance two professor brothers named Verlind, with a large sum of money to promote the theory: one was a physicist and the other invented algebra to describe the theory. Meanwhile a guy named Tower Wang managed to generalize entropic gravity to general relativity. There are also noises of which I don't know the quality of looking for a "smoking gun" in the universe that would prove entropic gravity and not dark matter. we will wait Physics needs time.
    As soon as there is a physical basis, entropic gravity is given a competitive edge against dark matter and it becomes legitimate for many research groups in the world to invest energy in it. We don't know if it is true yet. But the same goes for dark matter.

  7. As I said, articles A and B are impressive. I added another point of view that I believe is important. There are alternative theories for dark matter, neither negligible nor on the fringes of science. Entropic gravity won the Spinoza Prize (the Dutch Wolf Prize, the Dutch Nobel Prize) at the rate of 2.5 million euros and the new algebra that accompanied it, and its union with general relativity, is the gluing of the initial gap of dark matter in giant steps. According to these theories, gravity weakens exponentially with distance as exp(-alpha*x), and there is no need for dark matter to explain the gap between Einstein's model and observations.

  8. This year, Professor Laura Mersini-Houghton published physical papers combining general relativity and string theory (quantum gravity) that disprove the possibility of black hole formation, singularities in space. To date, not one serious article has been received to refute the claim. There were articles dismissing her outright. These are not serious.

    Variable gravity and entropic gravity are coming out of the closet in a continuous process, and in particular in 2014, as alternative explanations for dark matter.
    The book "Modified entropic gravity revisited" was published in September 2014, examining alternative theories for dark matter
    To explain the gap between the structure of the universe and the currently known laws of gravity.

    A researcher named WANG made a generalization of entropic gravity, an alternative theory for dark matter, with general relativity
    The researcher's conclusion is that a set of constraints is required to unify the theories:
    inclusion of energy-momentum conservation and cosmological homogeneity and isotropy requirements
    These constraints greatly reduce the solution space originally possible in entropic gravity, and we still don't understand why.

  9. In the article it is written: "The approach of a comet to Mars is an event that occurs on average once in 8 million years", it seems to me that this is an event that happens more frequently, once in a few hundred years or at most a few thousand years, because it has already happened twice in recent years with Shumkar Levi 9 with Jupiter and now with this comet.
    In addition, in the section on dark matter, scientists brought wives. I think it's better that they bring evidence and not their wives.
    Good night
    Sabdarmish Yehuda

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