2019-06-01_All_About_Space

Liquid water is considered

essential to any form of life as we

know it, besides nutrients and

a source of energy. All of these

are found on Venus. Even though

the lower atmosphere and the

surface of Venus are quite hot,

the cloud layer found between

about 48 to 70 kilometres (30

to 44 miles) above the surface

is much cooler, allowing the

presence of liquid water. The

clouds are made up of droplets of

liquid sulphuric acid diluted with

water, as well as other chemicals

that can support life.

Being closer to the Sun, Venus

receives more sunlight per unit

area compared to Earth, but

the present cloud cover reflects

a large fraction back to space.

The rest is scattered by the

atmosphere and the clouds, a

small fraction is absorbed and an

even smaller amount reaches the

surface. At shorter wavelengths

the absorption by the clouds

and atmosphere is somewhat

greater due to the presence of

unknown substances. It has been

suggested that these could be

colonies of microorganisms.

Life certainly could have

evolvedonVenusinitspast

when it had surface liquid water

andmigratedtotheclouds,

where it may be present today.

Sanjay Limaye is a senior

scientist at the

University of

Wisconsin-Madison

Could there be

any forms of

life on Venus?

Did

you know?

The light released approximately

380,000yearsaftertheBigBang

isknownasthecosmic

microwave background (CMB)

and can be observed

today.

PLANETS

What is the farthest galaxy we know of?

Thefarthestgalaxycurrentlyknowniscalled

GN-z11andis13.4billionlightyearsaway.The

universeisestimatedtobe13.7billionyearsold,

which means that this galaxy was formed within

the first 300 million years of the universe, when

theuniversewasinitsinfancy.Atthistimethe

universe was a hot and violent place, and its scale

was much smaller than what it is today.

Thestarsinthisearlygalaxywere100-times

more massive than our Sun and appeared blue in

colour. It is unlikely for planetary systems to have

already formed around stars in this galaxy.

Studying distant galaxies tells us about the

state of the universe when it was very young,

and the galaxies that were forming in it at

the time. Nearby galaxies like Andromeda are

almostasoldasourMilkyWay,andtotracehow

galaxies like our Milky Way formed and evolved

astronomers must study galaxies at increasingly

large distances.

Thisissimilartoa70-year-oldpersonlooking

at pictures from their childhood. Having a picture

for every age during their lifetime will help

observechangesintheirappearanceovertime

and understand how they aged.

Aayush Saxena is a postdoctoral

researcher at Leiden Observatory in

the Netherlands

ASTRONOMY

After the Big

Bang the

universe had to

expand before

its first galaxies

could form

The surface

and clouds

of Venus are

much more

tempestuous

than Earth

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