Even after a million years, Voyager 1 won’t get far.

Launched in 1977, Voyager 1 is now over 15.4 billion miles (24.8 billion km) from Earth. It left the solar system in 2012, becoming the first human-made object to enter interstellar space. But when viewed on the scale of our galaxy, its path looks like a scratch on the surface of something unimaginably vast.

Traveling at about 38,000 mph (17 km/s), Voyager 1 will take nearly 40,000 years just to pass near another star – Gliese 445, 17.6 light-years away. To complete a single orbit around the Milky Way’s center? It would take over 400 million years.

The Milky Way is about 100,000 light-years wide. Even after one million years, Voyager 1 will still be drifting through the Orion Spur – a small arm between Sagittarius and Perseus – barely having moved across the galactic map.

And yet, it’s still sending signals home.

Its power source – a radioisotope thermoelectric generator – keeps its instruments alive, though NASA expects contact to fade sometime between 2025 and 2030. When it does, Voyager 1 will continue its silent voyage alone.

Onboard is the Golden Record – a time capsule filled with Earth’s languages, music, and greetings. It’s a message to the cosmos from a small blue planet, carried by a spacecraft that, even after a million years, will still be lingering near home.

It’s a humbling reminder: we’ve made it far. But we've got a long way to go.

https://tinyurl.com/nhzw6y4v

The sizes and rotation of planets in solar system

 

Why and how do planets rotate?

 

George Spagna, chair of the physics department at Randolph-Macon College, explains.

Stars and planets form in the collapse of huge clouds of interstellar gas and dust. The material in these clouds is in constant motion, and the clouds themselves are in motion, orbiting in the aggregate gravity of the galaxy. As a result of this movement, the cloud will most likely have some slight rotation as seen from a point near its center. This rotation can be described as angular momentum, a conserved measure of its motion that cannot change. Conservation of angular momentum explains why an ice skater spins more rapidly as she pulls her arms in. As her arms come closer to her axis of rotation, her speed increases and her angular momentum remains the same. Similarly, her rotation slows when she extends her arms at the conclusion of the spin.

As an interstellar cloud collapses, it fragments into smaller pieces, each collapsing independently and each carrying part of the original angular momentum. The rotating clouds flatten into protostellar disks, out of which individual stars and their planets form. By a mechanism not fully understood, but believed to be associated with the strong magnetic fields associated with a young star, most of the angular momentum is transferred into the remnant accretion disk. Planets form from material in this disk, through accretion of smaller particles.

In our solar system, the giant gas planets (Jupiter, Saturn, Uranus, and Neptune) spin more rapidly on their axes than the inner planets do and possess most of the system's angular momentum. The sun itself rotates slowly, only once a month. The planets all revolve around the sun in the same direction and in virtually the same plane. In addition, they all rotate in the same general direction, with the exceptions of Venus and Uranus. These differences are believed to stem from collisions that occurred late in the planets' formation. (A similar collision is believed to have led to the formation of our moon.)

https://bit.ly/3SecB13

The average jump height of a person on different planets

 

The average jump height of a person on earth and its equivalent in other worlds of the solar system

1 Day in Solar System

 

12 Fascinating Facts on Solar Energy

Greetings from Mission Control at NASA JPL

NASA/JPL-Caltech/SwRI/MSSS

The view from Juno as it zooms toward Jupiter's north pole. This was the last thing Juno saw before it powered down its instruments in preparation for entering Jupiter's orbit at 11:38pm Eastern on July 4.

WE'RE ON THE SCENE FOR THE JUNO SPACECRAFT'S ARRIVAL AT JUPITER TONIGHT

By Shannon Stirone

PASADENA, Calif. — Coming to you from the center of the universe.

After a 9am Pacific time press briefing, the Juno team updated the world with what we can expect from this evening's exciting arrival of Juno at Jupiter. The team is simultaneously thrilled and nervous while they await news of the outcome.

Juno is due to enter orbit around Jupiter at approximately 8:38pm PST (that's 11:38pm EST), after which there should be a sigh of relief heard around the world.

Juno is on a mission to better understand the biggest planet in our solar system. What makes this orbit insertion so dangerous is not only the speed that it’s traveling but the intense radiation environment at Jupiter. The team has more than prepared for the spacecraft to get blasted with harmful particles, but because we’ve never flown this close to Jupiter, they have no idea what could go wrong in this unfamiliar environment.

JPL released the last image taken from Juno five days ago after all of it’s nine instruments were turned off in preparation for orbit insertion. The image shows Jupiter and its four main moons looking tiny as Juno swoops in at 165,000 miles per hour.

The newsroom is slowly filling up with news media from around the world, as everyone comes together on this 4th of July to document this important scientific mission. Keep up with us here and on Twitter as we share fun photos and information live from mission control in Pasadena, California. And tune in later for the livestream of Juno's arrival at Jupiter!

The Water in Your Glass Might Be Older Than the Sun

The water you drink is older than the planet you’re standing on. CreditBiwa Studio/Getty Images

By NICHOLAS ST. FLEUR

Every Friday, we’ll offer a Trilobite talking point to help you bring a bit more science to your weekend conversations.

Earth is old. The sun is old. But do you know what may be even older than both? Water.

It’s a mystery how the world became awash in it. But one prevailing theory says that water originated on our planet from ice specks floating in a cosmic cloud before our sun was set ablaze, more than 4.6 billion years ago.

As much as half of all the water on Earth may have come from that interstellar gas according to astrophysicists’ calculations. That means the same liquid we drink and that fills the oceans may be millions of years older than the solar system itself.

The thinking goes that some of the ancient ice survived the solar system’s chaotic creation and came to Earth. To demonstrate that, researchers analyzed water molecules in oceans for indicators of their ancient past.

The clue comes in the form of something known as “heavy water.” Water, as you know, is made up of two hydrogen atoms and one oxygen atom. But some water molecules contain hydrogen’s chunky twin, deuterium. (It contains a neutron in its nucleus, whereas regular hydrogen does not.)

Photo

An illustration of how ancient water in the interstellar cloud drenched the solar system as the sun and planets formed. CreditBill Saxton, via, National Science Foundation, Associated Universities, Inc, National Radio Astronomy Observatory

Deuterium-rich water is found on other planets and moons, even here on Earth, but researchers are not sure where it came from. One idea is that much of the heavy water formed in the interstellar cloud and then traveled across the solar system.

Using a computer model, the scientists showed in a 2014 paper that the billions-of-years-old ice molecules could have survived the sun’s violent radiation blasts, and gone on to bathe a forming Earth and its cousins.

They concluded that remnants of that ancient ice remain scattered across the solar system: on the moon, in comets, at Mercury’s poles, in the remains of Mars’ melts, on Jupiter’s moon Europa — and even in your water bottle. Now that’s something to raise your glass to.

NEW FEATURES OF JUPITER'S GREAT RED SPOT

By Sarah Fecht

A PORTRAIT OF THE PLANET IN HIGH-RESOLUTION

very year, the Hubble Space Telescope snaps a family portrait of the Solar System. It images each planet in detail, giving scientists a chance to spot any changes over time.

Jupiter is the first to get its new close-up, and the new ultra-HD 4K images have revealed some interesting new features, including a rare wave just above the planet's equator, and a stringy feature in its Great Red Spot.

“Every time we look at Jupiter, we get tantalizing hints that something really exciting is going on,” said NASA planetary scientist Amy Simon in a press release. “This time is no exception.”

Jupiter's wave

NASA/ESA/Goddard/UCBerkeley/JPL-Caltech/STScI

The vertical lines point to the wave, while the arrows indicate cyclones.

Scientists haven't seen anything like Jupiter's wave since Voyager 2 flew past the gas giant in 1979. At the time, scientists thought it might have been a fluke, but the new observations suggests it's just rare. Similar waves can be seen in Earth's atmosphere when cyclones are forming.

During the 10-hour observation period, scientists could see the new filament that threads through the Great Red Spot (a storm larger than the entire Earth) twist and rotate.

Jupiter's filament

NASA/ESA/Goddard/UCBerkeley/JPL-Caltech/STScI

Before and after images show the movements of a filament that threads through Jupiter's red spot.

Jupiter's red spot is 150 miles shorter than it was last year, confirming that the giant storm continues to shrink.

The Year of Pluto

The New Horizons mission will help us understand worlds at the edge of our solar system by making the first reconnaissance of the dwarf planet Pluto and by venturing deeper into the distant, mysterious Kuiper Belt – a relic of solar system formation.