In the 1990s, scientists detected that the universe was actually accelerating in its expansion rather than decelerating due to gravity. Why this is occurring is not well understood. It is believed that dark energy may be behind the accelerating expansion of the universe. It is believed that this dark energy makes up about 68% of the universe, dark matter makes up 27% of the universe, and everything else in the universe which can be seen by our telescopes(galaxies, stars, planets, etc) make up about 5% of the universe.
The German X-ray telescope, eROSITA, was set to launch on June 22, 2019, and will launch from the Baikonur Cosmodrome, a former Soviet launch complex located in current day Kazakhstan. The telescope will be launched along with a parent satellite called Spektr-RG.
The eROSITA will mainly examine galaxy clusters for its search for dark energy because they could emit X-rays that can then allow the telescope to track how the galaxy clusters move as well as how fast they are traveling. The telescope will also examine the gas from supernovas, neutron stars, as well as the nuclei of the galaxies that contain black holes in their centers. eROSITA will map the X-ray emissions coming from all over the universe and will create a large set of data on the objects described above and will improve our understanding of the universe.
Jupiter’s moon Europa has a huge ocean beneath its icy surface and it used to be thought that sulfate salts dominate Europa’s oceans, but this may turn out not to be the case.
The Hubble Space Telescope has detected table salt on the surface of Europa according to a study. NASA’s Galileo spacecraft which orbited around Jupiter during the 1990s and the 2000s and spotted some unexpected yellow patches on the surface. Subsequent laboratory simulations showed that these patches may be indications of irradiated sodium chloride(Europa lies within Jupiter’s radiation belt). As a result, Trumbo et al. started a search for signs of sodium chloride in Europa using the Hubble Space Telescope Imaging Spectrograph(STIS).
Trumbo et al. observed a broad absorption line at 450 nanometers which corresponds to the absorption line of irradiated table salt, but this was only observed on the one hemisphere of the moon that always faces Jupiter. On top of this, these signs of irradiated sodium chloride were mainly concentrated in the active regions of Europa(which are located in the hemisphere facing Jupiter), the regions of Europa where materials from the ocean spew up to the surface. This hemisphere of Europa which constantly faces Jupiter is shielded from the sulfur compounds(which come from Jupiter’s moon Io) that rain down on Europa on its other hemisphere. Because of this, Trumbo et al. wrote in their study that the composition of elements in the active regions of Europa may be representative of what can be found in Europa’s subsurface ocean which implies that this sodium chloride may make up a big part of Europa’s oceans. It is unclear however whether this is true, however. While it is near certain that the sodium chloride is coming from Europa’s ocean underneath, it is uncertain that this sodium chloride does dominate the oceans of Europa. There is still a possibility of sulfate salts making up the majority of Europa’s oceans with sodium chloride being a minor part of it.
Nevertheless, this discovery is enough to reexamine the composition of Europa’s oceans and it brings new possibilities of the life that may inhabit Europa. This discovery also indicates that Europa is hydrothermally active. While there are still some uncertainties and questions to be answered about this discovery, the NASA Europa Clipper probe is expected to launch in the 2020s and should bring about a wealth of data to be examined by scientists and should give us a clearer picture of the composition of elements in Europa’s ocean.
The paper that made this discovery can be found here:
Many people imagine physicists as people who have advanced knowledge of mathematics and imagine them uncovering the secrets of our universe by using chalk and a blackboard to write and manipulate equations. This stereotype is somewhat true if we are referring to a time before this century. Now, with the advent of the computer revolution and programming languages, this stereotype no longer holds true. Knowledge of computers and programming holds a very important place in physics today and the traditional usage of pen and paper or blackboard and chalk is much less frequent than it used to be. There is one programming language that has become the most commonly used by physicists: python.
There are a few reasons why python has become the most popular programming language used by physicists. One reason is its ability to process and visualize data sets. Before this Origin, Excel, Matlab, etc were used in order to handle data. Now, python can be used to do what Excel, Matlab, Origin, etc could do.
Another reason why python is popular is because it is extendable. Python has a huge community for computation. There are many fundamental applications of physics that can be found in libraries and packages. Numpy and Scipy offer many predefined functions and are good for fast numerical work. They have built-in linear algebra, Fourier transforms, sparse matrices, etc. There are many other libraries used by the scientific community in python such as Sympy, Pandas, etc.
In addition to this python is an easy programming language to learn. This is very important because of the fact that physicists are not professional programmers and learning non-physics skills in programming is very time-consuming. Python is a very clean and readable language and on top of this, programs written in python can be run even when the operating system is changed.
Finally, there are two more reasons to note the popularity of the python programming language among physicists: its ability to bind with your browser as well as the fact that python can integrate with C and FORTRAN code.
Back in January 2019, the Chinese launched the rover Yutu-2 and landed on the moon. This mission is a follow up to China’s first moon landing(Chang’e 3). China’s Yutu-2 rover collected the first-ever samples from the moon’s mantle according to a study. These samples could be very useful in solving the mystery of how the moon was formed and how it evolved. Previous research on the topic of how the moon was formed concluded that the moon was covered in magma initially and as this magma solidified, dense minerals would have crystallized at the base, while lighter minerals would have floated to the surface. This could possibly explain why plagioclase(which is made up of light minerals such as aluminum or silicon) makes up about 98% of the lunar surface. This explanation of the formation and evolution of the moon is very similar to that of the other inner planets. However, there have been criticisms of this explanation for the formation and the evolution of the moon with critics saying that it is uncertain whether the early lunar surface had the right mixture of chemical and physical features for its minerals in order for the minerals in the early moon to have separated the way the model explains they did. One of the ways to figure out the origins of the moon is by analyzing the moon’s mantle. This has been attempted numerous times with NASA’s Apollo programs and the Soviet Union’s Luna probes, but these attempts have never succeeded. Scientists have suggested that instead of launching probes to drill into the lunar surface to bring back samples of the moon’s mantle, the probes can find samples of the mantle from the cosmic impacts on the moon. Now, with the Yutu-2 rover, Chinese scientists may have been able to successfully extract the first samples of the mantle of the moon using the method described above(finding samples of the mantle from cosmic impacts on the moon). The analysis of the wavelengths of these minerals revealed that they contained low calcium pyroxene and olivine, which essentially matches the predictions made by the model described above of the formation and evolution of the lunar surface. To read more about the findings of these Chinese scientists, view this study:
In the 2017 NASA Authorization act, US congress directed NASA to provide a technical and financial assessment of a human mission to Mars in 2033. NASA contracted with the Science and Technology Policy Institute to prepare this report for congress. STPI used the strategy that NASA had laid out in its “Exploration Campaign” report and finally came to the conclusion that NASA’s work in which is described in the “Exploration Campaign” report would take too long to complete to support a 2033 mission to Mars. Even without the budget constraints that NASA will face, the report concluded that “a Mars 2033 orbital mission cannot be realistically scheduled under NASA’s current and notional plans” and that a mission to Mars could be carried no earlier than 2037(best case scenario). One of the major factors that has led to this conclusion is the development of new deep space transport technologies. According to the report, the testing of these technologies will have to be done in 2022, which is highly unlikely. Taking into account the other technologies that will have to be developed, it is highly unlikely that a mission in 2033 would be feasible. This does not take into account of the fact that the mission would cost a whopping $120.6 billion dollars in the fiscal year 2037.
The Mars mission is a part of a bigger overall human spaceflight program with total costs of around $217.4 billion through 2037. This program also includes a series of missions to land on the moon. Fortunately, the report projected that the moon landing will take place in 2028 which happened to be the year that NASA was aiming for prior to Pence’s speech in March in which subsequently a 2024 moon landing goal was announced. The report was completed prior to this announcement, so the costs of a 2024 moon landing goal is not addressed.
According to common sense and physics, time can only move forward. The arrow of time can only move forward because of the second law of thermodynamics which states that entropy(disorder) increases over time. Researchers from the Moscow Institute of Physics and Technology teamed up with American and Swiss scientists and returned the state of an IBM quantum computer a fraction of a second into the past however.
At subatomic scales, physicists describe the state of systems using wave functions which shows all the possible states that the system could be in. With the passage of time, the location of the particle is more likely to be farther and farther away from its position in the initial time and the wave function spreads. Reversing the spread of the wave function is very difficult and is like trying to bring back an intact wine glass from a broken one, but this is exactly what the researchers did. It is nearly impossible for this to happen on its own, however, it is possible if the experiment is done in an extremely controlled environment, which is what a quantum computer allows. The researchers simulated a particle in the quantum computer with its wave function spreading out. They then wrote an algorithm that would reverse every single component of the wave function and pulled back the wave function to its initial state. This was accomplished without increased entropy elsewhere in the universe. Does this mean that the researchers had created a time machine and they had broken the second law of thermodynamics? This is not the case. The second law of thermodynamics does indeed state that entropy has to increase with the passage of time, but it does not state that entropy can never stay the same.
As more qubits(analogous to what are called “bits” which are the smallest units of data in ordinary computers) to were introduced into the experiment, the success rate of the experiment dropped because the complexity of the system had increased too much for the quantum computer to maintain tight control on all aspects of the system, and as a result, it would be harder to keep entropy in check making the time reversal experiment more difficult. In order to counter this issue and conduct time reversal on larger and more complex systems, larger quantum computers will have to be used.
One of the biggest head scratchers in astrophysics is finding where 1/3 of the mass of the universe went. Some have attempted to explain this with dark matter, but a team of astronomers working at NASA’s Chandra X-ray Observatory think that they may have found a way to discover where this missing matter is at. They are not talking about detecting dark matter, they are talking about detecting “non-dark” matter. The researchers plan to detect this matter by using one popular theory: the matter is hidden in thread like strings of gas distributed across the universe. In order to detect this, the team has turned to a quasar called H1821+643 which produces strong x-ray signals. The researchers reasoned that if this missing matter is in intergalactic filaments, the x-ray signals that they would receive from the quasar would be changed slightly and they could compare what they actually observed with what they had expected from the quasar. In order to make their search more “efficient”, the team is focusing only on some specific wavelengths of x-rays which could best show the effects of the filaments. The team compared this technique to a “search for animals in the vast plains of Africa.” Akos Bogdan, a co-author of the new research said that “we know that animals need to drink, so it makes sense to search around watering holes first.” So far, the team has identified 17 filaments through this technique and are calculating the amount of mass that they have. The calculations suggest that the universe’s missing mass is probably in these filaments.