If all goes according to plan today, here’s what we can hope to learn from the Juno probe

IT WAS the moment of truth for NASA scientists — and as the world watched, it didn’t disappoint.

A 1/4 scale model size of NASA's solar-powered Juno spacecraft is displayed at the Jet Propulsion Laboratory in Pasadena, California. Picture: Richard Vogel/AP

“JUNO, welcome to Jupiter.”

Those were the words that could be heard over the intercom at NASA headquarters as scientists celebrated the successful launch of its Juno spacecraft into Jupiter’s orbit.

The world watched with bated breath as the unmanned probe embarked on the crucial bid to slip into its target orbit.

After launching nearly five years ago, researchers held their breath for the moment of truth at 1:18pm AEST this afternoon.

That was the time an all important 35-minute window began in which the spacecraft kicked in its engines in a bid to slow down enough to be dragged into Jupiter’s gravitational pull, in what NASA scientists referred to as the crucial engine burn.

As it kicked off, all was going well and scientists on the ground were optimistic.

“Right now it looks like the main engine is doing well,” said Juno project manager Rick Nybakken at the midway point.

While he and his team were very excited prior to the end of the 35-minute period, he was quick to point out that “it’s a crazy place to go” and nothing is guaranteed.

NASA was shooting for a 53-and-a-half day orbit, which the space agency ultimately succeeded in hitting.

When confirmation came in the form of a three second beep from the probe, the control room erupted with cheers.

The truly hard part was done, but they weren’t in the clear just yet. Thirty minutes after the confirmation of success, NASA scientists had to turn the probe around to once again face the sun in order to get the electricity to power the solar powered spacecraft for the rest of the mission.

The space agency was again successful, and the festivities are set to continue into the night as NASA celebrates this historic event.

Success! Engine burn complete. #Juno is now orbiting #Jupiter, poised to unlock the planet's secrets. https://t.co/YFsOJ9YYb5

— NASA (@NASA) July 5, 2016

#Juno team just put a basketball court sized spacecraft into orbit around a radioactive gas giant 400 million miles away. Let that sink in.

— Jason Henry (@JasonMHenry) July 5, 2016

Engine burn complete and orbit obtained. I’m ready to unlock all your secrets, #Jupiter. Deal with it.

— NASA's Juno Mission (@NASAJuno) July 5, 2016

Joining in on the celebration was tech giant Google which has changed its logo to an animated gif of NASA scientists celebrating the incredible achievement.

The @google doddle right now! #Juno pic.twitter.com/iOKttnAwmw

— Chris G - NSF (@CwG_NSF) July 5, 2016

Now that we’re largely out of the woods, here’s what we can expect to learn now that the Juno space probe has been successfully launched into Jupiter’s orbit.

WHAT IS THE NATURE OF JUPITER’S CORE?

Jupiter’s composition is more of a mystery than anything else. Scientists currently believe the gaseous planet has a dense central core that may be surrounded by a layer of metallic hydrogen, with another layer of molecular hydrogen on top.

As NASA scientist Glenn Orton put it during a Q&A this morning: “The general question is what is the interior structure of Jupiter like, and that’s the main focus (of the mission).”

The big query is whether or not Jupiter’s core is solid. If that does prove to be the case, it will have a slight and measurable impact on Juno’s orbit.

A constant radio signal being sent to Juno and relayed back to Earth will give scientists a picture of the internal makeup of the planet.

Here's Juno's "heartbeat" being picked up by a receiver in Canberra, Australia. pic.twitter.com/FfW5L9luD8

— Michael Slezak (@MikeySlezak) July 5, 2016

THE ORIGINS OF EARTH AND HISTORY OF OUR SOLAR SYSTEM

Jupiter is surrounded by a thick and tumultuous layer of gas and cloud.

Juno will get so close to Jupiter’s inhospitable environment that it will be able to study its atmosphere giving unprecedented insight into its origins as well as the origins of other planets in our solar system, including Earth.

By better understanding Jupiter’s chemistry we will understand “what our solar system was like billions of years ago,” NASA’s Dr. Michelle Thaller said.

The huge gas planet was likely the first planet formed and had a major impact on the formation of other planets.

Like our sun, Jupiter is composed primarily of hydrogen and helium but is also imbued with other heavy elements fundamental to the creation of terrestrial planets.

The spacecraft will hunt for oxygen in the form of water in Jupiter’s atmosphere, which may help explain how Earth got its water.

It will also use microwave sounding to look for the abundance of another highly important element: nitrogen, in the form of ammonia.

“The stuff Jupiter has more of is the stuff we’re all made of,” Juno’s principal investigator Dr Scott Bolton told Gizmodo.

“We’re looking at the history of the volatiles that formed the Earth by going back and seeing how much Jupiter has.”

NASA renderings of the Juno spacecraft near Jupiter.

THE MYSTERY OF THE GREAT RED SPOT

The most prominent feature of the gaseous planet is the Great Red Spot, which is a giant spinning storm in Jupiter’s atmosphere larger than Earth that has lasted for centuries. However in recent years the spot has been mysteriously shrinking.

It was once an oval about 41,036km wide in the late 1880s but when observed in 2014 it had shrunk to its smallest known size of 16,495km across.

Juno will explore how deep into the atmosphere the Great Red Spot extends to give researchers a better understanding of its puzzling nature.

The Great Red Spot of Jupiter, June 26, 1996, observed by the Galileo #space probe from 1.8 million kilometers away. pic.twitter.com/zfhSTdMfRv

— Humanoid History (@HumanoidHistory) July 3, 2016

THE GREATEST LIGHT SHOW IN SPACE

Jupiter’s aurora lights are the brightest in the solar system, making Earth’s northern and southern lights look dim by comparison. The spectacular phenomena can stretch for tens of thousands of kilometres around the poles of the gaseous planet.

“Auroras that are bigger than the entire planet Earth,” NASA’s Dr Thaller said.

Juno will use sensors to identify the electrons and types of positive ions that produce the magical light show in order to allow researchers to better understand it.

JUPITER’S INTENSE MAGNETIC FIELD

Jupiter has a very dangerous magnetic field that creates a lot of high energy radiation. The planet’s magnetic field is nearly 20,000 times as powerful as our own — although it weakens with distance and at the cloud tops is only 20 times more intense than Earth’s surface field.

The Juno mission should give us greater understanding of Jupiter’s intense magnetic field.

Earth’s magnetic field is created by a combination of a liquid layer of iron, nickel and other metals around its inner solid core where the flow of liquid iron becomes electrically charged.

On Jupiter it’s believed the planet’s complex magnetic field is produced by electrical currents in the what is likely the rapidly spinning metallic hydrogen interior.

Journalists work in preparation for NASA's Juno spacecraft's orbit around Jupiter in the media centre at Jet Propulsion Laboratory, in Pasadena, California. Picture: Richard Vogel/AP