My Science School

On August 22, 1993, just days before the Mars Observer spacecraft was to enter orbit around Mars, it lost contact with the bases here on Earth. The $400 million spacecraft with an estimated overall project cost of $1 billion was designed to study and photograph the Martian surface, but ended in failure.

Following the success of the Mariner programme in the 1960s and early 70s, the Viking programme was the U.S.'s next foray towards our neighbouring planet, Mars. After the probes Viking 1 and Viking 2 successfully landed on the red planet in 1976, over a decade went by before America's next mission to Mars. That came in the way of the Mars Observer, which was launched in 1992 and had things going well until its ill-fated end.

The mid-1980s saw a high priority mission to Mars being planned to act and expand on the information already assimilated by the Viking programme. With the preliminary mission goals of studying and taking high-resolution photographs of the Martian surface, the Mars Observer spacecraft was initially to be launched in 1990, before being rescheduled to 1992.

Based on Earth-orbiting spacecraft

Based on a commercial Earth-orbiting communications satellite that had been converted into an orbiter for Mars, the spacecraft was built at a cost of $400 million. The payload was made up of a variety of instruments that included a Gamma Ray Spectrometer (GRS), Pressure Modulator Infrared Radiometer (PMIRR), Thermal Emissions Spectrometer (TES), Mars Observer Camera (MOC), and Mars Balloon Relay (MBR) among others.

The specific objectives of the mission were to find out the elemental characteristics of the Martian surface: defining Mars topography and gravitational field: establishing the nature of Mars magnetic field finding out the distribution and sources of dust and volatile material over a seasonal cycle: and exploring the Martian abmosphere. The MBR was designed to receive information from the planned Mars Balloon Experiment to be carried by a Russian mission for retransmission back to Earth.

Contact lost

The Mars Observer was expected to achieve all this by orbiting the planet for one Martian year (687 Earth days), giving it a chance to observe the planet through the different seasons. The science instruments in the payload were thus designed to study the geology, climate, and geophysics of Mars.

Following a successful launch on September 25, 1992, Mars Observer was scheduled to perform an orbital insertion manoeuvre 11 months later on August 24, 1993. Just days before it, however, on August 22, 1993, communication was lost with the spacecraft even as it was preparing to enter orbit.

When the Mars Observer failed to respond to messages radioed by the ground controllers here on Earth, further efforts to communicate were made-once every 20 minutes. Even though they were met with silence, further attempts were made, less regularly, until the mission was declared a loss on September 27, 1993 and no further attempts to contact were made after that

Propulsion system failure

In 1994, an independent board from the Naval Research Laboratory announced their findings regarding the failure. They suggested that the most probable cause of the communications failure must be a rupture of the fuel pressurisation tank in the propulsion system of the spacecraft

Regardless of what the reason was, an estimated cost of $1 billion, which included the price of the spacecraft along with the costs of space shuttle launching and processing of scientific data was lost. While the science instruments were reflown on two other orbiters, Mars Global Surveyor and 2001 Mars Odyssey, there is no telling if Mars Observer followed the automatic programming to go into Mars orbit flew by the planet, or even if it continues to operate.

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If we talk about ringed planets, more often than not every one of us will be talking about Saturn. This, despite the fact that all four giants in our solar system Jupiter, Saturn, Uranus, and Neptune - in fact have rings.

This is likely because Saturn has spectacular rings. While the rings of Jupiter and Neptune are flimsy and difficult to view with stargazing instruments traditionally used, the rings of Uranus aren't as large as that of Saturn's.

As Jupiter is bigger than Saturn, it ought to have rings that are larger and more spectacular than that of its neighbour. As this isn't the case, scientists from UC Riverside decided to investigate it further. Their results were accepted by the Planetary Science journal and are available online.

Dynamic simulation

A dynamic computer simulation was run to try and understand the reason why Jupiter's rings look the way they do. The simulation accounted for Jupiter's orbit, the orbits of Jupiter's four main moons, and information regarding the time it takes for rings to form.

The rings of Saturn are largely made of ice, some of which may have come from comets also largely made of ice. When moons are massive, their gravity can either clear the ice out of the planet's orbit, or change the ice's orbit such that it collides with the moons.

Massive moons

The Galilean moons of Jupiter Ganymede, Callisto, lo, and Europa- are all large moons. Ganymede, in fact, is the largest moon in our solar system. The four main massive moons of Jupiter would thus destroy any large rings that might form around the planet. This also means that Jupiter is unlikely to have had large. spectacular rings at any time in the past as well.

Ring systems, apart from being beautiful, help us understand the history of a planet. They offer evidence of collisions with moons or comets, indicating the type of event that might have led to their formation. The researchers next plan to use the simulations to study the rings of Uranus to find out what the lifetime of those rings might be.

Picture Credit : Google 

Scientists have achieved yet another historic feat by discovering a dormant black hole. It is for the first time that a dormant stellar-mass black hole orbiting a star has been detected in a nearby galaxy.

This new black hole is nine times the mass of the Sun and revolves around a blue star in the nearby Large Magellanic Cloud galaxy. Researchers have termed it "the first to be unambiguously detected outside our galaxy". The binary system has been christened VFTS243. This finding is cardinal because it will help us get more insights into what happens during the death of a star and how black hole pairs are formed.

Astrophysicist and the lead author of the new study Tomer Shenar remarked that they have found a 'needle in a haystack. The study was published in the Nature Astronomy journal.

How it was detected

In a binary system, two stars revolve around each other and when a star dies, it will lead to a black hole in orbit with the other companion star. Scientists detect black holes from the X-ray radiation they emit as they feed on the companion star.

In this case, the scientists found a massive star orbiting something that couldn't be observed.

Following further studies, scientists found out that it was a dormant black hole.

The stellar mass black holes are formed when a massive star dies and collapses in a supernovae explosion. But strangely, in this particular case, the star that led to the formation of the black hole in VFTS 243 went away without any explosion and literally vanished into a black hole. Scientists have termed it a direct-collapse scenario. This has led scientists to understand that all stars do not end their lives in supernova explosions and it gives insight into how black hole pairs are formed.

What is a Black Hole?

A black hole is a celestial body that has an immensely huge gravitational pull, so huge that nothing escapes it. Not even light can escape it! The black hole grows by accumulating matter that falls in it. An image of a black hole was captured for the first time in 2019.

What is the size of a Black Hole?

The tiniest black hole can be as tiny as an atom but it can have the mass of a huge mountain. The other is the stellar black hole and these can have a mass of more than 20 solar masses, which is 20 times more mass than our sun. And the biggest black holes are christened supermassive. Sagittarius A is a supermassive black hole.

How are Black Holes formed?

Black holes are formed at the end of the life of a big star. When a massive star, say one having more than 20 solar masses, collapses after its nuclear fuel depletes, it will collapse onto itself and become a black hole. This collapse leads to a supernova and a part of the star gets blown off into space.

So will our Sun turn into a Black Hole?

The Sun cannot turn into a black hole. For us, the Sun is big, but on a celestial scale, it is too small to collapse into a black hole! So, our Sun will only turn into a white dwarf.

Picture Credit : Google