Connect with us

Astronomy

The power sources of stars : explained

blank

Published

on

where-does-a-star-get-its-power-from

Stars are probably the most important objects in the Universe. They’re certainly the cosmic objects we’re most familiar with – just look up, whether it’s day or night, the sky is dominated by them. This is especially obvious, of course, during the day, since our Sun is a star; not a particularly remarkable one, but one hugely important to us. But what exactly are they and where do they get all their power from?

Essentially, stars are pretty simple creatures, at least at the very beginning. They form when huge clouds of mostly hydrogen gas collapse under the effect of gravity, getting hotter and hotter in the process. As the fledgling star heats up, the hydrogen gas gets ionized, which means it is so hot it loses the ability to hold electrons, thereby becoming a soup of protons. Eventually the temperature and pressure rise so much that they are finally able to counteract the effects of gravity, keeping the star in a sort of precarious hydrostatic equilibrium.

stars-and-nuclear-fusion

Diagram of nuclear fusion in stars

And here is where the magic happens, and by magic, I mean the process of nuclear fusion. Inside the star, the density and temperature are so great that protons and neutrons bang together at great energies, and through a rather convoluted process, hydrogen essentially fuses into helium. OK, but how do we get from fusing subatomic particles to the huge burning spheres we usually see stars as? Well, this fusion process isn’t entirely “efficient”, so to speak. In other words, the end result is “lighter” than the sum of the ingredients we put in. The “lost” mass isn’t lost at all, but in fact it’s converted into energy, following Einstein’s famous E=mc2 equation.

Thus, the energy released (E) is the equivalent of the mass converted (m) times the speed of light (c) squared. Now of course, while the speed of light is a huge number (almost 300 000 km per second!), the amount of matter converted is incredibly small (a fraction of the mass of a proton), but on the scale of a star, this adds up to a lot. In the case of our Sun, it’s about 4 to 5 million tons of matter every second, which you can think of (if you want to try to wrap your head around these figures) as detonating 400 billion one megaton nuclear bombs. Every second. And it’s this same process that powers all the hundreds of billions of stars in each of hundred billion of galaxies throughout the Universe.

Who doesn’t enjoy listening to a good story. Personally I love reading about the people who inspire me and what it took for them to achieve their success. As I am a bit of a self confessed tech geek I think there is no better way to discover these stories than by reading every day some articles or the newspaper . My bookcases are filled with good tech biographies, they remind me that anyone can be a success. So even if you come from an underprivileged part of society or you aren’t the smartest person in the room we all have a chance to reach the top. The same message shines in my beliefs. All it takes to succeed is a good idea, a little risk and a lot of hard work and any geek can become a success. VENI VIDI VICI .

Astronomy

The Eta Aquariids meteor shower is occurring this month, and its peak can be observed at a specific time

blank

Published

on

blank

Currently, Earth is undergoing one of its three most active meteor showers. The Eta Aquariids, remnants of Halley’s comet, are observed during the month of May. During this period, Earth approaches the comet’s orbit at a distance of approximately 9.7 million kilometers (6 million miles), which is close enough to collect residual dust particles.

The Eta Aquariids exhibit a frequency of up to one meteor per minute, although this level of activity is limited to individuals residing near the equator and in the southern tropics. For the rest of the population on Earth, it is anticipated that there will be a more moderate but still highly respectable rate of 10 to 30 meteors per hour. The optimal time in the Northern Hemisphere is during the pre-dawn period when the sky is at its maximum darkness, particularly in areas located away from urban centers. The midnight hours are also favorable in the Southern Hemisphere.

Allow approximately 30 minutes for your eyes to adapt; thus, it is important to take this into account. The duration of the meteor shower spans from April 19 to May 28 annually. The zenith of meteor activity is anticipated to occur during the nights of May 5th and 6th; however, there is a high probability of observing numerous meteors throughout the entire week.

Our orbit intersects with the orbit of Halley’s comet twice annually. In May, this event results in the occurrence of a meteor shower. In October, the remnants form the Orionid meteor shower. The Eta Aquariids derive their name from their origin at the star Eta Aquarii.

Halley’s comet exhibits significant luminosity and possesses a comparatively brief orbital period, completing one revolution around the sun every 76 years. For a period of more than 2,250 years, humans have been engaged in the act of observing it. The earliest documented sighting of this phenomenon occurred in 240 BCE and was recorded in the Book of Han by Chinese astronomers in 12 BCE. The year 1066 witnessed the depiction of this event in two significant historical records: the Bayeux Tapestry, which documented the Norman Conquest of England, and the petroglyphs created by the Chaco, indigenous Americans in present-day New Mexico.

The appearance of a comet in 1301 inspired Giotto di Bondone to depict the Star of Bethlehem as a comet, which had a lasting influence on its portrayal for the next seven centuries. Although observations had been made for thousands of years, it was not until 1705 that Edmond Halley discovered the periodicity of them.

The most recent observation of the object from Earth occurred in 1986, and it is expected to return to the inner solar system in 2061. Currently, it is returning to its original position after reaching its maximum distance from the sun in December.

Continue Reading

Astronomy

NASA and ESA are making preparations for the imminent close approach of the near Earth object Apophis

blank

Published

on

blank

NASA and the European Space Agency (ESA) are making preparations for the imminent approach of asteroid 99942 Apophis, a near-Earth object.

Apophis, an asteroid considered highly dangerous to Earth, will approach within 32,000 kilometers (20,000 miles) of the Earth’s surface in 2029. This close encounter will allow scientists to closely examine the object. The asteroid will be visible from the Eastern Hemisphere without the need for a telescope or binoculars, and it will be closer than some of our man-made satellites.

blank

At the ESA-organized workshop Apophis T-5 Years: Knowledge Opportunity for the Science of Planetary Defense, scientists have been proposing potential missions to investigate the asteroid prior to the close approach.

NASA has already scheduled a visit to the asteroid, which is known as OSIRIS APEX. The objective is to reutilize the asteroid sampler previously referred to as OSIRIS-REx, deploying it to rendezvous with the asteroid soon after its close passage.

“According to NASA, the planned mission is expected to result in the alteration of the asteroid’s orbit, changes in its rotational speed and axis, and the potential occurrence of quakes or landslides that will modify its surface due to the gravitational pull of our planet,” NASA explains. The OSIRIS-APEX mission will enable terrestrial scientists to observe these alterations. In addition, the OSIRIS-APEX spacecraft will descend towards the surface of Apophis, an asteroid composed of silicate material (also known as rocky material) and a combination of metallic nickel and iron. It will then activate its engines to dislodge loose rocks and dust. This maneuver will provide scientists with a glimpse into the composition of the material located directly beneath the surface of the asteroid.

According to Space News, private companies presented alternative missions for the asteroid at the ESA meeting.

Blue Origin plans to utilize its Blue Ring spacecraft to transport a maximum of 13 payloads, weighing a combined total of 2 metric tons, to the asteroid. The launch is scheduled for 2027, with the spacecraft reaching the asteroid just before it comes closest to Earth. Meanwhile, NASA’s Jet Propulsion Laboratory presented the details of its DROID mission, which focuses on distributed radar observations of interior distributions.

JPL explains in a proposal that the architecture of DROID requires a specific launch of three spacecraft: a Mothership of ESPA Grande-class and two CubeSats. The Mothership transports the CubeSats to Apophis, follows a planned trajectory to meet up with them, captures detailed images using a specialized camera, and serves as a communication hub for the constellation by directly relaying data to Earth. After thoroughly characterizing Apophis’s physical attributes, such as its shape, spin, and gravity field, the Mothership releases two CubeSats. Each CubeSat is equipped with a wide-angle camera and low-frequency radar (operating at 60 MHz, using JuRa technology). These CubeSats then position themselves in synchronized low orbits to conduct radar observations using both monostatic and bistatic techniques.

Although the flyby of Apophis is expected to provide valuable insights into planetary defense against similar objects, there is no reason to be alarmed by its presence.

In 2021, Apophis conducted a close approach to Earth, during which astronomers conducted high-resolution radar observations to more accurately determine its orbital path. Prior to that, NASA held the belief that there was a possibility of a collision occurring later in the century. However, the observations conducted have definitively disproven this hypothesis.

“The possibility of a 2068 impact is no longer feasible,” stated Davide Farnocchia, an expert from NASA’s Center for Near-Earth Object Studies. “Our calculations indicate that there is no risk of impact for at least the next 100 years.”

Continue Reading

Astronomy

NASA has recently received a laser message transmitted from a massive distance of 226 million kilometers

blank

Published

on

blank

NASA’s Psyche mission is currently en route to investigate an unusual asteroid, and while in transit, the mission team has been conducting trials of a novel communication system. The novel methodology employs an infrared laser instead of radio waves, and it has recently demonstrated its efficacy from the farthest location to date. The message was sent when Psyche was located at a distance of 226 million kilometers (140 million miles) from Earth. That is equivalent to 1.5 astronomical units, which is the distance between the Earth and the Sun.

Psyche was transmitting its engineering data via radio waves using NASA’s Deep Space Network. For the first time, the mission team made the decision to transmit the data using the Deep Space Optical Communication system. The previous transmissions did not contain spacecraft data but rather test data.

During the April 8 test, it was demonstrated that data could be downloaded at a maximum rate of 25 Mbps, even from that distance. This already exceeds the anticipated target of “at least 1 Mbps” and is 10 to 100 times swifter than radio transmissions.

“During a pass on April 8, we received approximately 10 minutes of replicated spacecraft data through downlink,” stated Meera Srinivasan, the operations lead for the project at NASA’s Jet Propulsion Laboratory (JPL). Previously, we had been transmitting test and diagnostic data through our downlinks from Psyche. This marks a noteworthy achievement for the project as it demonstrates the integration of optical communications with a spacecraft’s radio frequency communications system.

blank

In previous tests, the spacecraft was positioned at a much shorter distance, specifically tens of millions of kilometers. Photographs and even a video featuring a cat were transmitted from the far reaches of outer space. The technology exhibits potential, yet there remain a few issues that require resolution. Clouds obstruct optical observations, preventing them from being conducted. This issue doesn’t affect radio communications.

“We have gained extensive knowledge about the system’s limits through our experiments during clear weather conditions. However, occasional storms have caused disruptions in operations at both Table Mountain and Palomar,” stated Ryan Rogalin, the receiver electronics lead of the project at JPL.

In June, the team will conduct another round of testing on the system when Psyche is located at a distance from the Sun that is 2.5 times greater than the distance between Earth and the Sun. This represents the utmost distance separating Mars and Earth. If the approach is successful, it could enable the establishment of a data-intensive network connecting Earth and Mars.

Continue Reading

Trending