Name: We've Never Seen a Pulsar Explode Like This | SciShow News
Uploaded: 2020-03-30T03:52:28.000Z
Duration: 6 min 57 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Human space exploration is all the rage these days,

Participle clauses with adverbial meaning

with NASA and other organizations racing to get astronauts on the Moon and beyond.

But one UK-based startup is dreaming of something a little different.

They want to populate the Moon with robots.

And instead of building a traditional, multi-wheeled rover, they're designing ones with legs.

The company Spacebit announced their plans in October,

revealing models of their crawling, jumping, kind of adorable mini-robots.

These unnamed “walking rovers” are based on designs of CubeSats,

small, boxy spacecraft we've been launching since 2003.

They have a mass of about one kilogram, only cost a few million dollars to produce,

and can be put together in less than a single year.

Their small size means Spacebit can send more than one in a single rocket launch,

and they can access parts of the Moon that larger, wheeled rovers can't.

That includes features like cracks, crevices, and even lava tubes:

hollow tunnels formed by ancient streams of lava.

This kind of exploration will help reveal a lot about the Moon's geology,

and it could also pave the way for future human missions.

Scientists have proposed that, if we ever want to live on the Moon,

living under its surface, like in a lava tube, might be a good idea.

That would protect us from a lot of the Sun's radiation,

and there wouldn't be such drastic temperature changes over the course of a lunar day.

But that's a plan for the distant future.

For this first rover mission, things will be a little simpler.

In 2021, a single Spacebit rover will travel to the Moon on a lunar lander

from the company Astrobotic, along with more than a dozen other confirmed payloads,

Then, once our little robot buddy is on the surface,

it will send back some high-def video and LIDAR data, basically,

3-D maps made by shooting out laser beams and having the light bounce off of things.

The rover won't go very far or last very long, though.

It will only walk about ten meters from the lander, and likely will only last one lunar day,

because it can't survive the Moon's nighttime temperatures.

But if all goes well, we might be seeing a lot more of these new mini-rovers!

And they'll give us an opportunity to learn some cool stuff.

Of course, we've got plenty more technology out there right now,

studying farther and farther-flung reaches of the cosmos.

And last month in The Astrophysical Journal Letters,

one group of researchers reported that they'd found a massive explosion

that will help us better understand the universe's lighthouses, called pulsars.

it can leave behind a collapsed core made mostly of neutrons: a neutron star.

When one of those objects spins fast enough and emits enough radiation,

we see it from Earth as a pulsating light.

The pulsar in question, called J1808 for short, is about 11,000 light-years away.

We discovered it back in 1996 when a satellite saw it release a giant flare of X-ray radiation.

And since then, we've seen it flare every two to four years.

But J1808's most recent explosion, technically referred to as a Type I X-ray burst,

It was picked up in August by NASA's NICER telescope on the International Space Station,

and in only 20 seconds, it released as much energy as our Sun does in about ten days.

But that wasn't the most interesting part:

It was the fact that this pulsar had a combination of traits that's never been observed in the same flare.

For context, X-ray bursts happen when J1808 steals hydrogen gas from its companion,

a gaseous body called a brown dwarf that orbits the pulsar.

Over time, the pulsar steals enough gas that some of it rains down onto the pulsar's surface.

There, it's hot enough and there's enough pressure that the bottom layer of hydrogen

undergoes nuclear fusion and turns into helium.

And when there's enough helium, it explodes, and you get an X-ray burst.

Typically, these bursts get brighter, hit a peak, and then fade away.

But this last burst from J1808 didn't do that.

Instead, about half a second after its flare started,

the amount of X-rays it released suddenly stopped increasing.

And then it continued on and reached maximum intensity.

Astronomers think that this happened because of specific events on the pulsar's surface.

They believe that, right after the flare kicked off,

the blast built up enough energy to throw any remaining hydrogen back into space.

That created the apparent stall in the curve.

Then, the flare continued, and the helium layer rapidly expanded, too,

although it cooled and contracted again shortly afterward.

The whole burst was more or less over in about a minute.

But even though the event was short, it's significant.

This is the first evidence that actually shows two separate ejection events

during a pulsar's X-ray outburst; one for hydrogen, and the other for helium.

By itself, that opens up the ability for astronomers to study

the differences between these events and make sure they align with our models.

And that wasn't the only weird thing that happened here.

After all that, J1808 got about 20 percent brighter for a few seconds.

And we don't know why that happened; at least, not yet.

Additionally, researchers found a few other things, like evidence of X-ray flashes

that happened at other locations on the pulsar's surface.

These features have all been seen across other pulsar outbursts,

none of its other captured flare-ups have produced the same results.

This makes the burst an important piece of evidence for understanding pulsars.

It shows that the rules governing these objects can be so complex

that the same body doesn't react the same way every single time.

That might seem a little annoying, for space stuff to suddenly throw something new at you,

It means we have a chance to really pin down our understanding of how the universe works.

This edition of SciShow Space News is brought to you by

this episode's President of Space: SR Foxley.

SR Foxley is one of our patrons on Patreon, and is part of an amazing community

that supports SciShow and loves learning together.

We're really grateful for our patrons, so if you're one of them, thank you.