It’s not just a case of the universe “existing”. It also needs the conditions for life to exist, or we couldn’t ask the question. See link -
leaderu.com/science/ross-justright.html
More than two dozen parameters for the universe must have values falling within narrowly defined ranges for life of any kind to exist.
1.strong nuclear force constant
If larger: no hydrogen; nuclei essential for life would be unstable
If smaller: no elements other than hydrogen
2.Weak nuclear force constant
If larger: too much hydrogen converted to helium in big bang, hence too much heavy element material made by star burning; no expulsion of heavy elements from stars
If smaller: too little helium produced from big bang, hence too little heavy element material made by star burning; no expulsion of heavy elements from stars
3.Gravitational force constant
If larger: stars would be too hot and would burn up too quickly and too unevenly
If smaller: stars would remain so cool that nuclear fusion would never ignite, hence no heavy element production
4.Electromagnetic force constant
If larger: insufficient chemical bonding; elements more massive than boron would be too unstable for fission
If smaller: insufficient chemical bonding
5.Ratio of electromagnetic force constant to gravitational force constant
If larger: no stars less than 1.4 solar masses hence short stellar life spans and uneven stellar luminosities
If smaller: no stars more than 0.8 solar masses, hence no heavy element production
6.Ratio of electron to proton mass
If larger: insufficient chemical bonding
If smaller: insufficient chemical bonding
7.Ratio of numbers of protons to electrons
If larger: electromagnetism would dominate gravity, preventing galaxy, star, and planet formation
If smaller: electromagnetism would dominate gravity, preventing galaxy, star, and planet formation
8.Expansion rate of the universe
If larger: no galaxy formation
If smaller: universe would collapse prior to star formation
9.Entropy level of the universe
If smaller: no proto-galaxy formation
If larger: no star condensation within the proto-galaxies
10.Mass density of the universe
If larger: too much deuterium from big bang hence stars burn too rapidly
If smaller: insufficient helium from big bang, hence too few heavy elements forming
11.Velocity of light
If faster: stars would be too luminous
If slower: stars would not be luminous enough
12.Age of the universe
If older: no solar-type stars in a stable burning phase in the right part of the galaxy
If younger: solar-type stars in a stable burning phase would not yet have formed
13.Initial uniformity of radiation
If smoother: stars, star clusters, and galaxies would not have formed
If coarser: universe by now would be mostly black holes and empty space
14.Fine structure constant (a number used to describe the fine structure splitting of spectral lines)
If larger: DNA would be unable to function; no stars more than 0.7 solar masses
If smaller: DNA would be unable to function; no stars less than 1.8 solar masses
15.average distance between galaxies
if larger: insufficient gas would be infused into our galaxy to sustain star formation over an adequate time span
if smaller: the sun¹s orbit would be too radically disturbed
16.average distance between stars
if larger: heavy element density too thin for rocky planets to form
if smaller: planetary orbits would become destabilized
17.decay rate of the proton
if greater: life would be exterminated by the release of radiation
if smaller: insufficient matter in the universe for life
18.12Carbon (12C) to 16Oxygen (16O) energy level ratio
if larger: insufficient oxygen
if smaller: insufficient carbon
19.ground state energy level for 4Helium (4He)
if larger: insufficient carbon and oxygen
if smaller: insufficient carbon and oxygen
20.decay rate of 8Beryllium (8Be)
if slower: heavy element fusion would generate catastrophic explosions in all the stars
if faster: no element production beyond beryllium and, hence, no life chemistry possible
21.mass excess of the neutron over the proton
if greater: neutron decay would leave too few neutrons to form the heavy elements essential for life
if smaller: proton decay would cause all stars to collapse rapidly into neutron stars or black holes
22.initial excess of nucleons over anti-nucleons
if greater: too much radiation for planets to form
if smaller: not enough matter for galaxies or stars to form
23.polarity of the water molecule
if greater: heat of fusion and vaporization would be too great for life to exist
if smaller: heat of fusion and vaporization would be too small for life¹s existence; liquid water would become too inferior a solvent for life chemistry to proceed; ice would not float, leading to a runaway freeze-up
24.supernovae eruptions
if too close: radiation would exterminate life on the planet
if too far: not enough heavy element ashes for the formation of rocky planets
if too frequent: life on the planet would be exterminated
if too infrequent: not enough heavy element ashes for the formation of rocky planets
if too late: life on the planet would be exterminated by radiation
if too soon: not enough heavy element ashes for the formation of rocky planets
25.white dwarf binaries
if too few: insufficient fluorine produced for life chemistry to proceed
if too many: disruption of planetary orbits from stellar density; life on the planet would be exterminated
if too soon: not enough heavy elements made for efficient fluorine production
if too late: fluorine made too late for incorporation in proto-planet
26 ratio of exotic to ordinary matter (deleted due to character restrictions on post). Available at link.
Anyone who believes this universe just popped into being without a shred of intelligent design needs their head read.