Explore the galactic map that could guide aliens to Earth

BY MATTHEW W. CHWASTYK & DIANA MARQUES

The original map contained four elements

What is a pulsar?

After a supernova—the titanic explosion of a massive star—the star’s core can become incredibly dense. It is called a “pulsar” if it’s set spinning, emitting radio waves that appear to pulse on and off like a lighthouse.

The Crab Nebula is a supernova remnant with a pulsar at its core.

To make a new map,

start with stable signposts

If a small, dense pulsar is paired with another star, it siphons material and energy from its companion, accelerating the pulsar’s already rapid rotation.

At up to 43,000 rotations per minute, the radiation appears to pulse and acts like a beacon. This system is a reliable signpost for mapping within the Milky Way.

Then, add reference points

Much like how the Global Positioning System (GPS) works on Earth, these galactic beacons could provide a map to the sun. By identifying these specific pulsars and how much their

spins have changed, you reveal the sun’s location—and Earth is right nearby.

Finally, add a universal ruler

Our measurements of time and distance would be unfamiliar

to aliens. Hydrogen is a good universal alternative. When a hydrogen electron flips the direction of its spin, it emits a radio wave with a wavelength

of about 21 centimeters, the distance light travels in just

over 0.7 nanoseconds.

The new map

SEAN MCNAUGHTON; NEW PULSAR MAP: SCOTT RANSOM; MILKY WAY: ANTOINE COLLIGNON

SOURCES: NASA GODDARD SPACE FLIGHT CENTER; NATIONAL RADIO ASTRONOMY OBSERVATORY; HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS

Explore the galactic map that could guide aliens to Earth

BY MATTHEW W. CHWASTYK & DIANA MARQUES

The original map

What is a pulsar?

After a supernova—the titanic explosion of a massive star—the star’s core can become incredibly dense. It is called a “pulsar” if it’s set spinning, emitting radio waves that appear to pulse on and off like a lighthouse.

The Crab Nebula is a supernova remnant with a pulsar at its core.

To make a new map, start with stable signposts

If a small, dense pulsar is paired with another star, it siphons material and energy from its companion, accelerating the pulsar’s already rapid rotation. At up to 43,000 rotations per minute, the radiation appears to pulse and acts like a beacon. This system is a reliable signpost for mapping within the Milky Way.

Then, add reference points

Much like how the Global Positioning System (GPS) works on Earth, these galactic beacons could provide a map to the sun. By identifying these specific pulsars and how much their spins have changed, you reveal the sun’s location—and Earth is right nearby.

Finally, add a universal ruler

Our measurements of time and distance would be unfamiliar to aliens. Hydrogen is a good universal alternative. When a hydrogen electron flips the direction of its spin, it emits a radio wave with a wavelength of about 21 centimeters, the distance light travels in just over 0.7 nanoseconds.

The new map

These new coordinates might more accurately guide extraterrestrial life to Earth for the next billion years or so. Both more distant and relatively closer guide pulsars are used. The map encodes how quickly rapidly spinning pulsars rotate (rotational periods) and how quickly star-pulsar systems revolve around each other (orbital periods).

Earth in the Milky Way

SEAN MCNAUGHTON; NEW PULSAR MAP: SCOTT RANSOM; MILKY WAY: ANTOINE COLLIGNON

SOURCES: NASA GODDARD SPACE FLIGHT CENTER; NATIONAL RADIO ASTRONOMY OBSERVATORY; HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS

Explore the galactic map that could guide aliens to Earth

BY MATTHEW W. CHWASTYK & DIANA MARQUES

The original map

What is a pulsar?

After a supernova—the titanic explosion of a massive star—the star’s core can become incredibly dense. It is called a “pulsar” if it’s set spinning, emitting radio waves that appear to pulse on and off like a lighthouse.

The Crab Nebula

is a supernova remnant with a pulsar at its core.

To make a new map, start with stable signposts

If a small, dense pulsar is paired with another star, it siphons material and energy from its companion, accelerating the pulsar’s already rapid rotation. At up to 43,000 rotations per minute, the radiation appears to pulse and acts like a beacon. This system is a reliable signpost for mapping within the Milky Way.

Then, add reference points

Much like how the Global Positioning System (GPS) works on Earth, these galactic beacons could provide a map to the sun. By identifying these specific pulsars and how much their spins have changed, you reveal the sun’s location—and Earth is right nearby.

Finally, add a universal ruler

The new map

These new coordinates might more accurately guide extraterrestrial life to Earth for the next billion years or so. Both more distant and relatively closer guide pulsars are used. The map encodes how quickly rapidly spinning pulsars rotate (rotational periods) and how quickly star-pulsar systems revolve around each other (orbital periods).

Earth in the Milky Way

SEAN MCNAUGHTON; NEW PULSAR MAP: SCOTT RANSOM; MILKY WAY: ANTOINE COLLIGNON

SOURCES: NASA GODDARD SPACE FLIGHT CENTER; NATIONAL RADIO ASTRONOMY OBSERVATORY; HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS

Explore the galactic map that could guide aliens to Earth

BY MATTHEW W. CHWASTYK & DIANA MARQUES

The original map

What is a pulsar?

The Crab Nebula

is a supernova remnant

with a pulsar at its core.

To make a new map, start with stable signposts

Then, add reference points

Much like how the Global Positioning System (GPS) works on Earth, these galactic beacons could provide a map to the sun. By identifying these specific pulsars and how much their spins have changed, you reveal the sun’s location—and Earth is right nearby.

Finally, add a universal ruler

The new map

Earth in the Milky Way

READ THE FULL STORY

NASA sent a map to space to help aliens find Earth. Now it needs an update.