Whether or not you believe in life beyond Earth, there are actually a minimum of 100 billion planets in our universe, according to a NASA study.

But how many planets make up our solar system?

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How many planets are there in our solar system?

There are eight planets in our solar system, which is part of the Milky Way.

Pluto was once called the ninth planet in our solar system, but the International Astronomical Union made some category changes in 2006 and Pluto became a minor or dwarf planet.

The main reason for this decision is that the generic orbit of Pluto intersects the orbit of Neptune.

The idea of ​​a ninth planet has persisted, and astronomers are now looking for Planet X, or Planet Nine, after mathematical evidence from 2016.

Planet Nine is thought to be five thousand times the mass of Pluto and 10 times the mass of Earth, and orbiting beyond Neptune.

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What is the order of the planets in our solar system?

The planets in our solar system are generally classified according to their distance from the Sun, Mercury being the closest.

Half of the eight planets are known as terrestrial or interior planets – Mercury being closest to the Sun, followed by Venus, Earth, then Mars.

The other half is made up of Jovian or Jupiter-type planets. In order of distance from the Sun, these are Jupiter, Saturn, Uranus and Neptune.

These last four are massive compared to the four inner planets and are made up of gases like hydrogen, helium and nitrogen.

Jupiter and Saturn are often called the gas giants, while Uranus and Neptune are called the ice giants.

It is believed that they probably all have solid cores.

There are many mnemonics for learning the order of the planets, one of the most popular of which is: My highly educated mother just served us noodles.

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How many planets have been discovered?

It is believed that there are 4,108 identified exoplanets in and beyond our solar system.

NASA tweeted in January 2021: “So far we have discovered 4,108 exoplanets – planets beyond our solar system.

“Most of these worlds orbit other stars, but not all of them. ‘Rogue planets’ are not linked to any star as they move through space in darkness.”

Very few of these planets have been considered as potentials to support life forms.

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For a variety of reasons, astronomers assume that there is one planet for every star, although in reality some stars do not have planets orbiting and others have several.

There are at least 400 billion stars in our own galaxy, so billions in the entire universe.

Stars are all different from each other, as are galaxies, and even planets, so we can’t just multiply information about our own galaxy or solar system.

Planets can be gaseous or rocky, hot or frozen, and can orbit near their star or billions of miles away.

There are two main methods used to try to identify planets orbiting other stars.

The first is the Stella-wobble method, which uses gravity studies over long periods of time to try to establish the mass and radius of potential planets.

The second is the Transit method, which examines how planets can partially block light from their star.

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New Delhi: Scientists have discovered that the Oort Cloud, a spherical layer of icy objects on the edge of the solar system, could harbor countless interstellar objects belonging to our solar system.

In 2019, astronomers spotted a rebellious comet from another star system in our solar system. Named Borisov, the frozen snowball was the first and only interstellar comet ever detected by man.

But the new study suggests these interstellar visitors are more common in the solar system than you might think. In fact, they may outnumber objects in the solar system.

Prior to the detection of the first interstellar comet, theory about the formation of planetary systems suggested that there should be fewer visitors than permanent residents.

The latest study, which makes calculations based on the conclusions drawn from Borisov, suggests that interstellar visitors outweigh objects originating in the solar system.

The Oort Cloud spans an area between 200 and 10,000 billion kilometers from the Sun, and unlike stars, Oort Cloud objects do not produce their own light. These two factors make the debris in the outer solar system difficult to see.

Observations with next-generation technology can help confirm the team’s results. The launch of the Vera C. Rubin observatory in Chile, scheduled for 2022 for example, will perhaps detect many more visitors like Borisov. Read more.

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Read also : Asteroid with the solar system’s shortest orbital period spotted and human DNA from 7,200 years ago

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A treasure trove of ancient elephant bone tools found in Italy

Scientists have discovered a mine of tools made from elephant bones in Italy, dating back around 400,000 years, some of which would only become objects of common use 100,000 years ago.

Although the use of bone tools was common at the time, it was the way they were made that impressed scientists.

Researchers recovered the tools from a site called Castel di Guido not far from modern Rome. Hundreds of thousands of years ago there was a stream that attracted thirsty 13-foot-tall creatures called straight-tusked elephants.

Scientists believe elephants would sometimes die of natural causes near the stream, and ancient humans put the remains to good use.

These Stone Age dwellers produced tools using a systematic and standardized approach, much like a single individual working on a primitive assembly line.

The team believe humans back then were breaking elephant long bones in a standardized way and producing standardized parts to make bone tools. This kind of skill did not become mainstream until much later.

About 400,000 years ago, Neanderthals were just beginning to emerge in Europe. Researchers suspect that these ancient humans (whose tools have now been found) were in fact Neanderthals.

Some of the tools were sharp and could have been used to cut meat. Others were wedges that might have been useful for splitting elephant’s heavy thighbones and other long bones.

The team also discovered a single artifact carved from a bone of wild cattle that looks like what archaeologists call a “smoother,” or straightener, a type of tool that ancient humans used to process leather. But such tools did not become mainstream until about 300,000 years ago. Read more.

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Read also : Rare fossil turtle egg discovered belongs to species that died when asteroid wiped out dinosaurs

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Scientists decode how certain bacteria generate electricity

Scientists have identified a hair-like protein hidden inside bacteria that serves as a sort of on-off switch for nature’s ‘power grid’, which is a global network of nanowires generated by bacteria that permeates all oxygen-free soils and deep ocean floors.

Scientists hope to use this natural power grid to generate electricity, new biofuels, and even self-healing electronic components.

Almost all living things breathe oxygen to get rid of excess electrons when converting nutrients into energy. Without access to oxygen, however, soil bacteria living deep under the oceans or buried underground for billions of years use tiny protein filaments called nanowires to get rid of excess electrons. Electrons in motion are what create electricity

However, how these soil bacteria exhale electricity has remained a mystery. Since 2005, scientists thought that nanowires were made of a protein called “pili” that many bacteria present on their surface.

However, scientists have found that these nanowires are made up of totally different proteins.

For the new study, the researchers used electron cryomicroscopy to reveal that this pili structure is made up of two proteins and that instead of serving as nanowires themselves, the pili remain hidden inside bacteria and act as pistons, pushing the nanowires into the environment. Read more.

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Continents could merge into a supercontinent in 250 million years

Using computer models to travel in time, the researchers predicted two possible scenarios for the evolution of the Earth, 250 million years later. Both involve all the continents moving together to form the next supercontinent.

The first scenario predicts the formation of the Aurica supercontinent, a low latitude supercontinent. Aurica will have very little snow or ice and an average temperature of around 20 degrees Celsius.

The second possibility is that a super continent called Amasia forms at a high latitude, with a smaller Antarctic subcontinent in about 200 million years. Amasia will be a continent dominated by snowfall and ice caps.

This bright, white supercontinent will reflect more solar heat and have a climate similar to that of Earth’s last ice age.

The researchers said these predictions of how Earth might evolve could help find exoplanets (planets outside the solar system) that may once have hosted life. Read more.

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Read also : Reason for Jupiter’s high temperature and how Stonehenge survived the test of time

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Russian part of ISS threatened with irreparable failures

A Russian space official this week voiced concerns over the deterioration of the Russian segment of the International Space Station, warning that obsolete hardware could lead to “irreparable failures.”

According to Vladimir Soloviev, chief engineer of the rocket and the space company Energia, 80% of the flight systems in the Russian segment have reached the end of their service life.

Energia, a maker of spacecraft and space station components, is the primary developer of the Russian section of the ISS, a joint venture with the United States, Canada, Japan and the European Space Agency.

Russia had previously indicated that it plans to leave the ISS after 2025 and launch its own orbital station. The official also said that small cracks were found on the Russian Zarya cargo module. Launched in 1998, it is one of the oldest modules of the ISS.

In addition, in July, the entire ISS had briefly tilted out of orbit after the thrusters of a new Russian module re-ignited several hours after docking. Read more.

(Edited by Poulomi Banerjee)

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The Spitzer Space Telescope, launched in 2003, is on a mission to become NASA’s first infrared light observatory. It gave astronomers an unprecedented infrared view of the universe, allowing us to peer into regions of space hidden from optical telescopes with unprecedented clarity and sensitivity. One of NASA’s great observatories, Spitzer discovered a ring of Saturn, studied some of the most distant galaxies, and identified two of the most distant supermassive black holes ever discovered, among other accomplishments during its 16 years of operation.

The study of exoplanets – planets outside of our solar system – was not one of Spitzer’s original goals. But innovations during his mission improved Spitzer’s accuracy and allowed him to become an essential tool for work on exoplanets. Spitzer marked a new era in planetary science by being the first telescope to directly detect light from exoplanets. He has played a key scientific role in everything from planets larger than Jupiter to small, rocky worlds that can be Earth-like.

In 2017, Spitzer helped reveal TRAPPIST-1, the first known system of seven Earth-sized planets. The discovery set a new record for the most habitable zone planets found around a single star outside of our solar system. Spitzer’s data also showed that all of these planets are likely rocky. The TRAPPIST-1 study takes scientists one step closer to answering the question “Are we alone?”

This poster depicts the TRAPPIST-1 planets, some of which were discovered by Spitzer. The physical characteristics of the planets are currently not known, beyond their mass and their distance from the star TRAPPIST-1, which is visualized in the background. The James Webb Space Telescope should teach us more about this fascinating system.

The majestic Northern and Southern Lights have mystified humans for millennia. During the long, dark winter nights – when the space weather is good – green and purple clouds can cover the polar sky from horizon to horizon. The glowing lights dance and move in curtains and arcs, forming a crescendo of color before disappearing.

The terrestrial auroras are not alone in our solar system either. Telescope observations and visiting spacecraft have found evidence of auroras on Saturn, Jupiter, Mars, Venus – and even exoplanets. And with a recent discovery on Jupiter’s mysterious “dawn of dawn” published in the journal AGU Advances, astronomers continue to unravel the mysteries of these lights throughout our solar system.

Aurora on Earth

Auroras on Earth are created when our planet is bombarded by particles from the Sun, mainly electrons and protons. These particles travel down Earth’s magnetic field lines, where they collide with nitrogen and oxygen and excite molecules until they glow. The basic mechanics are not too different from a simple neon.

And yet the Northern Lights and the Northern Lights continue to confuse astronomers’ attempts to predict them and explain their many nuances. For example, just recently a group of citizen scientists discovered a whole new type of aurora, which they dubbed “Steve”. And some researchers are now even trying to find out whether auroras can make sounds – an idea that recurs regularly in folklore but has generally been rejected by science.

More and more, astronomers are also discovering that our planet is not the only one with auroras. Yet not all of them function quite the same as the Earth.

Aurora on Venus

Venus completely lacks a magnetic field. So if Earth’s auroras are caused by interactions with our planet’s magnetic field, then surely Venus shouldn’t have any Northern Lights at all. Right?

And yet, for forty years, astronomers have wondered about the strange green signals observed on images of the planet.

Scientists moved closer to solving the mystery in 2014. A team of researchers using a telescope in New Mexico observed that Venus was repeatedly struck by solar storms. Each time, green excited oxygen signals appeared.

This evidence, combined with observations collected by the European Space Agency’s Venus Express spacecraft, suggests that the Sun’s own magnetic field could be extended to the planet by solar wind. This process is sufficient to create auroras.

Aurora on Mars

Like Venus, Mars also has auroras despite its extremely weak magnetic field. And the auroras of Mars are made even more incredible because the red planet orbits twice as far from the Sun as Venus.

Nearly two decades ago, ESA’s Mars Express spacecraft caught a startling glow in the planet’s upper atmosphere. It turns out that the aurorae of Mars are unlike anything else in the solar system.

While the Red Planet lost its magnetic field a long time ago, observations from spacecraft show that magnetic anomalies still persist today, scattered across the planet’s crust. And these regions correspond to the areas where the residual magnetic field of Mars is strongest. So when charged solar particles hit the planet, they interact with this patchwork of magnetism and produce faint, scattered auroras.

Aurora over Jupiter

In the far reaches of our solar system, astronomers have seen auroras on Jupiter, Saturn, Uranus and Neptune. Auroras on these gas giant planets likely have similar mechanisms, although Uranus and Neptune have only been visited once by spaceships.

Of all, Jupiter is home to the most spectacular light show in the solar system, as the Hubble Space Telescope has shown us in great detail. Its aurorae are absolutely massive in size thanks to a magnetosphere about 20,000 times more powerful than that of Earth.

They never stop either. While Earth’s auroras fired their spark only from the Sun, Jupiter also receives a constant dose of charged particles from its volcanic moon, Io.

Hubble observed the auroras for an extended and particularly active period in 2016 that coincided with the arrival of orbiter Juno to Jupiter. As Hubble observed the planet, the arriving probe measured the solar wind. Together, the spacecraft has provided new insight into how Jupiter’s auroras react to charged particles from the Sun.

A new study published in March 2021 provided additional information. Before the arrival of the Juno spacecraft, astronomers could not observe the auroras on the day side of Jupiter. And as the spacecraft scanned the night side of Jupiter, it spotted the emergence of extremely bright auroras called “dawn storms.” These storms produce hundreds of times more energy than a nuclear reactor on Earth. And for the first time, this new study has followed storms from their origins on the night side of the planet to their full evolution to the day side.

It turns out that they form much like a kind of aurora on Earth called an auroral sub-storm. Here they are caused by sudden and “explosive” reconfigurations of our planet’s magnetosphere as the solar wind varies. But on Jupiter, the process is probably related to changes in the plasma from Io.

Aurora on a rogue planet

In 2018, astronomers discovered a huge gas giant planet about 20 light years away, dubbed SIMP j01365663 + 0933473. With a mass 13 times that of Jupiter, it traverses our original starless galaxy, making it a so-called “rogue planet”. These worlds formed without stars or were thrown out of their solar systems.

SIMP j01365663 + 0933473 also appears to have a magnetic field millions of times stronger than that of Earth with auroras that can put our northern lights to shame. According to a 2018 study in The Journal of Astrophysics, its auroras occur through a process totally different from anything that happens in our solar system.

Without a star to bombard it with charged particles, SIMP j01365663 + 0933473 must have another source. This could mean that this rogue planet does not wander the galaxy completely on its own. Like Jupiter and Io, it may have a volcanically active moon that feeds it with charged particles. Or, alternatively, like so many different aurora mechanisms that astronomers have discovered over the years, SIMP j01365663 + 0933473 may hold some surprises as well.

Concept art by 21 / Borisov. Image: NRAO / AUI / NSF / S. Dagnello

In the summer of 2019, amateur astronomer Gennadiy Borisov spotted a rogue comet that originated in a star system far beyond the Sun. The comet, named 2I / Borisov, was just the second interstellar intruder ever to be identified in our solar system, after sighting the bizarre ‘Oumuamua object in 2017.

While ‘Oumuamua sparked heated controversy over its strange nature and possible origins, 2I / Borisov fascinated scientists for the opposite reason: it looked roughly like local comets orbiting the Sun, suggesting that the visitor may come from a system very similar to our own.

Now, independent findings from two research teams have strengthened this link between our solar system and the mysterious birthplace of 2I / Borisov, while also revealing a surprising new twist on local and interstellar comets.

Piotr Guzi and Michał Drahus, two scientists from Jagiellonian University in Poland, announced the “unexpected discovery” of nickel vapor in the atmosphere of 2I / Borisov, according to a study published Wednesday in Nature. Although it is well known that heavy metals such as iron and nickel exist as solids inside comets, these elements had never been seen except in gaseous form when comets approach stars, causing extreme heating which triggers the sublimation of the metals into vapor.

This is why Guzi and Drahus were caught off guard by clear evidence of gaseous nickel in the coma or the atmosphere of 2I / Borisov, even though the interstellar comet was about twice as far from the Sun as Earth at the time of the team observations in January 2020 At this distance, the comet’s temperature was estimated to be around -93 ° C, well below the conditions of 425 ° C that normally produce gaseous nickel.

Yet the team’s observations, obtained by the sophisticated X-shooter spectrograph at the European Southern Observatory’s Very Large Telescope, showed evidence of nickel gas over several nights, “effectively removing[ing] the possibility of confusion with a background source or instrumental artefacts, ”according to the study.

“Atomic nickel was a truly unexpected discovery, as observation of the gaseous form of any metal was considered to be limited only to warm environments, such as comets grazing the sun passing a few solar rays from the surface of the Sun. “Guzi said in an email.

“The two brightest nickel lines were clearly visible in our combined spectrum, but since we knew of no typical emissions at these wavelengths, we first made sure that they were present in the spectra taken each night. , and not in the background of the sky. and that they are not artefacts, ”he continued. “Yet it took us a long time to discover their true nature. “

To potentially explain the discovery, Guzi and Drahus propose that heavy metal vapor can be released at cold temperatures through a process known as photodissociation, in which photons (light particles) stimulate a nickel-containing molecule on the surface. to sublimate into gas.

The team’s findings would be quite intriguing in themselves, but they also coincide with the publication of a decades-long compositional study of comets in our solar system, led by University of Liège astronomer Jean Manfroid. . Using observations collected since 2002, the Manfroid team discovered that nickel and iron “are ubiquitous in cometary atmospheres, even far from the Sun”, according to a study also published on Wednesday in Nature.

“We learned of the other document while ours was already under review,” Guzi said. “The fact that the presence of nickel was detected both in the coma of the first known interstellar comet and in a collection of comets originating in our planetary system is simply astonishing.”

“This opens up a new perspective for understanding how the formation of planetary systems takes place in the galaxy since comets are seen as the remnants of this process,” he added.

The new research also strengthens the hypothesis that 2I / Borisov could have originated from a star system very similar to ours, as these studies identify yet another property that the interstellar visitor shares with our own local comets. If scientists find more interstellar comets that look like 2I / Borisov, it could hint at the existence of many solar system analogues across the Milky Way.

“We might expect the conditions at the place of their birth, as well as the chemical makeup of the interstellar cloud from which their original planetary system originated, to be similar to the interstellar cloud from which our solar system was born.” , Guzi said.

“It would be interesting to study the composition of other interstellar comets in the future to compare them with 2I / Borisov,” he continued. “Unfortunately, we don’t know when such an object will appear. The other fascinating question is what is the source of the metallic atoms in the gases surrounding the cometary nucleus.

Fortunately, these tantalizing questions could be answered in the years to come, as next-generation observatories will increase the speed at which interstellar visitors are spotted. In particular, the Vera C. Rubin observatory in Chile, which is due to enter service in the coming years, should speed up the detections of these mysterious intruders.

A larger census of interstellar objects will provide vital information about their distant home systems, highlighting how unique our own cosmic neighborhood is as part of the Milky Way.

“This is an important period in the history of planetary science, because we have the opportunity to study objects born in distant planetary systems and which have been ejected from their homes on their way to our cosmic neighborhood,” Guzi concluded.

Instruments aboard NASA’s Voyager 1 spacecraft, which nine years ago left the far reaches of our solar system, picked up the faint, monotonous sound of outer space

Scientists exploring the far reaches of our solar system have detected a strange “buzz”.

The instruments aboard NASA’s Voyager 1 spacecraft, which nine years ago left the far reaches of our solar system, picked up the low, monotonous sound.

Experts said this was due to the constant vibrations of small amounts of gas found in the near vacuum of interstellar space.

It represents the background noise present in the vast expanse between star systems, according to a study published this week in the journal Nature Astronomy.

These vibrations, called persistent plasma waves, have been identified at radio frequencies in a narrow bandwidth over a period of three years as Voyager 1 travels through interstellar space.

Stella Koch Ocker, PhD student in astronomy at Cornell University and lead author of the study, said: “The persistent plasma waves we have just discovered are far too weak to actually be heard with the human ear.

“If we could hear it, it would sound like a single stable note, playing constantly but changing very slightly over time.”

The Voyager 1 spacecraft, launched in September 1977, is currently located about 14.1 billion kilometers from Earth, about 152 times the distance between our planet and the sun, and continues to obtain and transmit data.

Having visited the enormous planets Jupiter and Saturn decades ago, Voyager 1 now provides a glimpse into interstellar space.

Voyager 1 has previously detected gas disturbances in interstellar space triggered by occasional flares from our sun.

The new study reveals stable vibrations unrelated to solar activity that could be a constant feature in interstellar space.

This hum has a frequency of about 3 kilohertz (kHz).

“When the oscillations of the plasma are converted into an audio signal, it looks like a varying tone. It’s a bit strange,” said James Cordes, professor of astronomy at Cornell University and co-author of the study.

“Voyager 1 will continue, but its power supply will most likely run out this decade after up to 50 years of service.

“Conceptual designs are underway for future probes aimed at going beyond the Voyager spacecraft.

“This is the message that I find appealing: our reach extends into interstellar space.”