Tonight's Sky
Sun
Sun
Moon
Moon
Mercury
Mercury
Venus
Venus
Mars
Mars
Jupiter
Jupiter
Saturn
Saturn

Tonight's Sky — Change location

OR

Searching...

Tonight's Sky — Select location

Tonight's Sky — Enter coordinates

° '
° '

Using radio waves to peer back in time

Astronomers are planning huge radio arrays to investigate the birth of the first structures.
ska_reionization
One way astronomers map star-forming regions is by looking for a specific signature of neutral hydrogen; this tells scientists where these hydrogen clouds are. An electron can be in two energy states, and as it transitions from the higher-energy state to the lower-energy one, it emits radiation with a wavelength of 21 centimeters. Due to the universe’s expansion, light from distant objects has been stretched into lower-energy, and longer wavelength, radiation. This 21cm line thus has been redshifted into the radio regime.

Astronomy magazine subscribers can read the full article for free. Just make sure you're registered with the website.

Already a subscriber? Register now!

Registration is FREE and takes only a few seconds to complete. If you are already registered on Astronomy.com, please log in below.
ADVERTISEMENT

FREE EMAIL NEWSLETTER

Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter.

ADVERTISEMENT
ADVERTISEMENT
BoxProductcovernov

Click here to receive a FREE e-Guide exclusively from Astronomy magazine.

Find us on Facebook

Loading...