Venus and Saturn will be in conjunction this weekend, appearing side by side in the night sky during January's post-sunset "planet parade."

Do the periods of comets decrease because they lose mass every time they get near the Sun? Robert BaileyConover, Wisconsin Great question! Assuming you're referring specifically to the orbital period - in other words,

I pick out North America’s celestial highlights for the week ahead (which also apply to mid-northern latitudes in the northern hemisphere).

Both Venus and Saturn will be in the Aquarius constellation, the water bearer, during their close approach. To help spot it, viewers should look towards the south in the evening sky, using the bright star Fomalhaut in the nearby Piscis Austrinus constellation as a guide to locate Aquarius.

Plus: Saturn’s moon Iapetus is visible, our Moon passes the bright star Spica, and Mars skims south of Pollux in Gemini in the sky this week.

On Monday night you may have a chance to witness the moon obscuring the Red Planet at its brightest, as well as a comet’s closest approach to the sun.

Astronomer Dean Regas gives us the lowdown on the best things to look out for this winter, from a “planet parade” to the ATLAS comet.

NASA and famed astronaut Buzz Aldrin say stargazers have the best chance of catching a glimpse of Saturn and Venus in alignment starting Saturday. The planets have been shuffling toward each other in the sky and will appear closest this weekend, appearing only inches apart to the human eye.

Because planets always appear in a line, the alignment isn't anything out of the norm. What's less common is seeing so many bright planets at once.

Mars, Jupiter, Venus, Saturn, Uranus and Neptune are visible this month in a 'planetary parade'. Dr Becky Smethurst at the University of Oxford explains what to look out for

The enormous visitor to our solar system may have been about 8 times the mass of Jupiter, and come nearly as close to the sun as the orbit of Mars.

Because the period of an object does not depend on its mass, comets’ orbital periods remain unchanged due to mass loss.